Search

Serum erythropoietin (sEPO) is an initial screening tool for distinguishing polycythemia vera (PV) from secondary erythrocytosis (SE), but defining 'subnormal' sEPO levels for PV diagnosis remains contentious, complicating its clinical utility. This study compares the diagnostic performance of sEPO across established subnormal limits, including reference interval (RI), clinical decision limit (CDL), and functional reference limit. sEPO levels were analyzed in 393 healthy donors (HDs) and 90 patients (41 PV and 49 SE), who underwent bone marrow biopsy and genetic tests due to erythrocytosis. The RI (2.5–97.5 percentile from HDs) of sEPO was 5.3–26.3 IU/L. A CDL of 3.1 IU/L, determined by ROC analysis in erythrocytosis patients, had a sensitivity of 80.5% and specificity of 87.8% for diagnosing PV. A functional reference limit of 7.0 IU/L, estimated based on the relationship between sEPO and hemoglobin, hematocrit, and WBC, increased sensitivity to 97.6% but decreased specificity to 46.7%. Using 5.3 IU/L as a 'subnormal' limit identified all three JAK2-negative PV cases, increasing the sensitivity and negative predictive value to 97.6% and 97.0%, respectively. Combining the RI, CDL, and functional reference limit may improve PV diagnostic accuracy. [ABSTRACT FROM AUTHOR]

Secretoneurin (SN) is a novel cardiac biomarker that associates with the risk of mortality and dysfunctional cardiomyocyte Ca2+ handling in heart failure patients. Reference intervals for SN are unknown. SN was measured with a CE-marked ELISA in healthy community dwellers from the fourth wave of the Trøndelag Health Study (HUNT4) conducted in 2017–2019. The common, sex and age specific 90th, 95th, 97.5th and 99th percentiles were calculated using the non-parametric method and outlier exclusion according to the Reed test. The applicability of sex and age specific reference intervals were investigated using Harris and Boyd test. We also estimated the percentiles in a subset with normal findings on echocardiographic screening. The total cohort included 887 persons (56.4 % women). After echocardiographic screening 122 persons were excluded, leaving a total of 765 persons (57.8 % women). The 97.5th percentile (95 % CI in brackets) of SN was 59.7 (57.5–62.1) pmol/L in the total population and 58.6 (57.1–62.1) pmol/L after echocardiography screening. In general, slightly higher percentiles were found in women and elderly participants, but less than 4 % in these subgroups had concentrations deviating from the common 97.5th percentile. Low BMI or eGFR was also associated with higher concentrations of SN. Upper reference limits for SN were similar amongst healthy adult community dwellers regardless of prescreening including cardiac echocardiography or not. Women and elderly showed higher concentrations of SN, but the differences were not sufficiently large to justify age and sex stratified upper reference limits. [ABSTRACT FROM AUTHOR]

Background: This cross-sectional study aimed to explore the variation trend of renal function for healthy pregnant women at different gestational ages and aimed to establish RIs for renal function set tests according to the trimester of pregnancy. Methods: A total of 120 healthy pregnant women and 40 healthy non-pregnant women were enrolled in this study and divided into early trimester (1 - 13 weeks of gestation, n = 40), second trimester (14 - 27 weeks of gestation, n = 40), third trimester (≥ 28 weeks of gestation, n = 40), and a non-pregnant women group (n = 40). Analytes of UA, BUN, Cr, β2-MG, Cys-C, RBP, NAG, CO2, HCY, C1q, and NGAL were measured by using the analytical systems of the Second Xiangya Hospital. The RIs were defined by using non-parametric 95% intervals. Results: The RIs for UA, Cr, β2-MG, NAG, CO2, Hcy, and C1q were established for the first and second trimester group and the third trimester group. There were huge differences after pregnancy. The RIs for BUN were different for the 1 - 13 weeks group and the after 14 weeks group. There were significant differences for NGAL in pregnant and non-pregnant women, but not for Cys-C and RBP. Conclusions: The RIs for renal function tests in pregnant women were established, thus providing clinical reference intervals for the clinicians. [ABSTRACT FROM AUTHOR]

Objective To determine reference intervals (RI) for fasting blood insulin (FBI) in Brazilian adolescents, 12 to 17 years old, by direct and indirect approaches, and to validate indirectly determined RI. Methods Two databases were used for RI determination. Database 1 (DB1), used to obtain RI through a posteriori direct method, consisted of prospectively selected healthy individuals. Database 2 (DB2) was retrospectively mined from an outpatient laboratory information system (LIS) used for the indirect method (Bhattacharya method). Results From DB1, 29345 individuals were enrolled (57.65 % female) and seven age ranges and sex partitions were statistically determined according to mean FBI values: females: 12 and 13 years-old, 14 years-old, 15 years-old, 16 and 17 years-old; and males: 12, 13 and 14 years-old, 15 years-old, 16 and 17 years-old. From DB2, 5465 adolescents (67.5 % female) were selected and grouped according to DB1 partitions. The mean FBI level was significantly higher in DB2, on all groups. The RI upper limit (URL) determined by Bhattacharya method was slightly lower than the 90 % CI URL directly obtained on DB1, except for group female 12 and 13 years old. High agreement rates for diagnosing elevated FBI in all groups on DB1 validated indirect RI presented. Conclusion The present study demonstrates that Bhattacharya indirect method to determine FBI RI in adolescents can overcome some of the difficulties and challenges of the direct approach. [ABSTRACT FROM AUTHOR]

AbstractVitamin B1 (thiamine pyrophosphate (TPP)) and B6 (pyridoxal 5'- phosphate (PLP)) deficiencies pose significant health risks. The current measurement method employs High-Performance Liquid Chromatography (HPLC), though, Liquid Chromatography with tandem Mass Spectrometry (LC-MS/MS) is considered a more sensitive and selective analytical method. However, there is a lack of LC-MS/MS-based reference intervals. Moreover, none of the existing reference intervals are established in Danish populations. Therefore, the aim of this study was to establish a reference interval for whole blood concentrations of TPP and PLP in Danish blood donors using LC-MS/MS. Blood samples were collected from healthy Danish blood donors and analysed using the reagent kit, MassChrom® Vitamins B1 and B6 in whole blood (Chromsystems Instruments & Chemicals GmbH, Munich, Germany) for quantitative determination of both TPP and PLP concentration in whole blood, using LC-MS/MS. Reference intervals were determined with non-parametric methods as the 2.5th and 97.5th percentile and presented with 90% confidence intervals (CI). In total 120 blood donors were included. The concentrations of TTP or PLP were not statistically different between sexes just as age did not affect the concentrations, hence, combined reference intervals were employed. The resulting reference intervals are: TPP, nmol/L: 101.0 (90% CI: 96.4–108.5) − 189.0 (90% CI: 184.7–192.0) and PLP, nmol/L: 64.0 (90% CI: 60.9–66.7) − 211.8 (90% CI: 168.3–231.0). In conclusion, reference intervals for whole blood TTP and PLP in a healthy Danish population were established based on a LC-MS/MS method. Furthermore, the reference intervals were not affected by age or sex. [ABSTRACT FROM AUTHOR]

Background/Objectives: We present a software package called reflimR (Version 1.0.6), which enables rapid and transparent verification of reference intervals from routine laboratory measurements. Our method makes it easy to compare the results with specified target values and facilitates the interpretation of deviations using traffic light colors. Methods: The algorithm includes three procedural steps: (a) definition of an appropriate distribution model, based on Bowley's quartile skewness, (b) iterative truncation, based on a modified boxplot method to obtain the central 95% of presumably inconspicuous results, and (c) extrapolation of reference limits from a truncated normal quantile–quantile plot. Results: All algorithms have been combined into one consolidated library, which can be called in the R environment with a single command reflim (x). Using an example dataset included in the package, we demonstrate that our method can be applied to mixed data containing a substantial proportion of pathological values. It leads to similar results as the direct guideline approach as well as the more sophisticated indirect refineR software package. As compared to the latter, reflimR works much faster and needs smaller datasets for robust estimates. For the interpretation of the results, we present an intuitive color scheme based on tolerance ranges (permissible uncertainty of laboratory results). We show that a relatively high number of published reference limits require careful reevaluation. Conclusions: The reflimR package closes the gap between direct guideline methods and the more sophisticated indirect refineR method. We recommend reflimR for the rapid routine verification of large amounts of reference limits and refineR for a careful analysis of unclear or doubtful results from this check. [ABSTRACT FROM AUTHOR]

Simple Summary: Some trace elements are essential for the health of vertebrates, but only limited data are available on blood levels in tortoises. The aim of this study was therefore to measure trace elements in heparinized blood plasma of Hermann's tortoises (Testudo hermanni) (n = 520) from March to September 2022 using inductively coupled plasma mass spectrometry (ICP-MS) and to establish specific reference intervals. Additionally, the influence of sex, season, and region of sample collection on the measured values were evaluated. Significant (p ≤ 0.05) sex-specific, seasonal, and regional differences were found for a number of trace elements indicating that all of these factors should be considered when establishing and interpreting blood trace element levels in tortoises. Some trace elements are essential for the health of vertebrates, but little is known about their function, the amounts required, and the factors influencing their metabolism in tortoises. The aim of this study was therefore to measure trace elements (chromium (Cr), cobalt (Co), copper (Cu), iron (Fe), magnesium (Mg), manganese (Mn), molybdenum (Mo), selenium (Se), zinc (Zn)) in heparinized blood plasma of Hermann's tortoises (Testudo hermanni) (n = 520) from March to September 2022 using inductively coupled plasma mass spectrometry (ICP-MS) and to establish specific reference intervals. Additionally, the influence of sex, season, and region of sample collection on the measured values were evaluated. Significant (p ≤ 0.05) sex-specific differences were found for Cu, Mg, and Mn; seasonal differences were found for Cr, Cu, Mn, Mo, and Se; and the region in which the tortoises were kept significantly impacted Cr, Cu, Fe, Mg, Mo, and Se levels. The results show that all of these factors should be consider when establishing and interpreting blood trace element levels in tortoises. [ABSTRACT FROM AUTHOR]

Background: CA19-9 is elevated in pancreatic cancer and other malignancies, and commonly used in clinical practice. Unfortunately, CA19-9 immunoassays are not harmonized, and reference intervals may differ between assays. The aim of this study was to establish the reference interval of the ADVIA Centaur/Atellica IM CA19-9 assay in an apparently healthy Singapore adult population. Methods: This is a retrospective cross-sectional study. De-identified data from Health Screening participants were extracted from our database. Subjects with biochemical results suggesting anaemia, diabetes mellitus, viral hepatitis or abnormal liver, and renal and tumour markers were excluded. Outlier and subclass analyses by age and sex were performed. CA19-9 reference limits and 90% confidence intervals were then determined for candidate subclasses. Results: Data from 12,174 subjects (5846 males and 6328 females) were available after exclusion criteria were applied. CA19-9 results did not follow a normal distribution and were higher in females compared to males (P <.001). Although CA19-9 means were statistically different between certain age groups, the evaluable 99th percentile reference limits were not statistically different. The overall 99th percentile reference limits for the Centaur/Atellica CA19-9 assay was 37 U/mL for males 21–80 years, and 60 U/mL for females 21–80 years. Conclusions: Our results suggest that separate CA19-9 reference intervals should be applied for males and females. [ABSTRACT FROM AUTHOR]

Background: To accurately assess hypogammaglobulinemia at birth, it is essential to determine the reference intervals of serum immunoglobulin (IgG) levels in newborns. In the present study, we determined the gestational age (GA)-/birth weight (BW)-dependent percentile-based reference intervals of serum IgG levels and converted them into simple formulas for practical use. Methods: Serum IgG levels were measured in cord blood from 2902 newborns delivered at 22 to 41 weeks of GA or 264 to 4642 g of BW after exclusion of those with congenital disorders. Linear regression analysis was used to correlate GA and UC-IgG levels and BW and UC-IgG levels. After calculation of the percentile values of UC-IgG levels for each GA or BW, the distributions were approximated by the least-squares method. Fitness was evaluated by the coefficient of determination (R 2 ). Results: Significant positive correlations were found both between GA and UC-IgG levels (r s = 0.790, P < 0.001) and BW and UC-IgG levels (r s = 0.626, P < 0.001). The distribution of the 5%ile of UC-IgG levels (Y) by GA or BW (X) was approximated as a straight line (Y = 37.5 *X – 775.8; Y = 0.161 *X + 95.34, respectively). The fitness was stronger in the GA-derived formula than the BW-derived formula (R 2 = 0.973 vs 0.913). Conclusions: We established GA-/BW-dependent reference percentile-based intervals for serum IgG levels using cord blood from 2902 newborns without congenital disorders. Using GA-dependent reference intervals may be useful for assessing hypogammaglobulinemia at birth. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Modern Laboratory Medicine is the property of Journal of Modern Laboratory Medicine Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objective: To determine reference intervals (RI) for fasting blood insulin (FBI) in Brazilian adolescents, 12 to 17 years old, by direct and indirect approaches, and to validate indirectly determined RI. Methods: Two databases were used for RI determination. Database 1 (DB1), used to obtain RI through a posteriori direct method, consisted of prospectively selected healthy individuals. Database 2 (DB2) was retrospectively mined from an outpatient laboratory information system (LIS) used for the indirect method (Bhattacharya method). Results: From DB1, 29345 individuals were enrolled (57.65 % female) and seven age ranges and sex partitions were statistically determined according to mean FBI values: females: 12 and 13 years-old, 14 years-old, 15 years-old, 16 and 17 years-old; and males: 12, 13 and 14 years-old, 15 years-old, 16 and 17 years-old. From DB2, 5465 adolescents (67.5 % female) were selected and grouped according to DB1 partitions. The mean FBI level was significantly higher in DB2, on all groups. The RI upper limit (URL) determined by Bhattacharya method was slightly lower than the 90 % CI URL directly obtained on DB1, except for group female 12 and 13 years old. High agreement rates for diagnosing elevated FBI in all groups on DB1 validated indirect RI presented. Conclusion: The present study demonstrates that Bhattacharya indirect method to determine FBI RI in adolescents can overcome some of the difficulties and challenges of the direct approach.

Motasim Jawi,1 Hadiah Bassam Al Mahdi,2,3 Hussam Daghistani,4,5 Yousef Almoghrabi,4,5 Rami Algahtani,6 Dalal Tawati,7 Mohammed R Algethami,8 Yasser Noorelahi,9 Zuhier Awan4 1Department of Physiology, College of Medicine, University of Jeddah, Jeddah, Saudi Arabia; 2Al Borg Medical Laboratories, Al Borg Diagnostics, Research and Development Unit, Jeddah, Saudi Arabia; 3Department of Biological Sciences, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia; 4Department of Clinical Biochemistry, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia; 5Regenerative Medicine Unit, King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia; 6Department of Medicine, College of Medicine, Umm Al-Qura University, Makkah, Saudi Arabia; 7Department of Obstetrics and Gynecology, King Abdullah Medical Complex, Jeddah, Saudi Arabia; 8Department of Family and Community Medicine, College of Medicine, University of Jeddah, Jeddah, Saudi Arabia; 9Department of Radiology, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi ArabiaCorrespondence: Motasim Jawi, Department of Physiology, College of Medicine, University of Jeddah, Jeddah, Saudi Arabia, Tel +966 569191939, Email mmjawi@uj.edu.saPurpose: Blood Lp(a) concentration is recognized as an independent risk factor for cardiovascular disease (CVD). Population-based lipoprotein(a) (Lp[a]) research in Saudi Arabia is rare. Thus, the primary goal of this pilot study was to identify age- and sex-specific reference ranges for Lp(a) levels, in addition to the associations between Lp(a) levels and other atherosclerotic markers in Saudi individuals.Patients and methods: A five-year retrospective study of Lp(a) and lipid markers in Saudi patients was conducted using the Al-Borg diagnostics database (2015– 2020). The population sample consisted of 361 Saudi individuals aged 18– 93 years (162 males, 199 females). An immunoturbidimetric technique was used to determine Lp(a) concentration.Results: The mean and median Lp(a) levels in the study population were 35 nmol/L and 50 nmol/L, respectively. Sex and age did not influence Lp(a) values. Lp(a) values showed a minor correlation with other atherosclerotic markers when the Pearson correlation coefficient was used. In Saudi Arabia, the distribution of Lp(a) concentrations is skewed to the left, favoring lower values.Conclusion: Lp(a) levels in individuals residing in Saudi Arabia were comparable to those observed in other ethnic groups. Additionally, standardizing Lp(a) measurements according to sex and age may enhance broader applicability and facilitate comparisons across different populations. However, larger studies are required to provide more comprehensive data for comparison.Keywords: lipoprotein(a), lipids, cardiovascular disease, reference range, reference interval, Saudi Arabia

Abstract Background The aim is to establish and verify reference intervals (RIs) for serum tumor markers for an apparently healthy elderly population in Southwestern China using an indirect method. Methods Data from 35,635 apparently healthy elderly individuals aged 60 years and above were obtained in West China Hospital from April 2020 to December 2021. We utilized the Box-Cox conversion combined with the Tukey method to normalize the data and eliminate outliers. Subgroups are divided according to gender and age to examine the division of RIs. The Z-test was used to compare differences between groups, and 95% distribution RIs were calculated using a nonparametric method. Results In the study, we observed that the RIs for serum ferritin and Des-γ-carboxy prothrombin (DCP) were wider for men, ranging from 64.18 to 865.80 ng/ml and 14.00 to 33.00 mAU/ml, respectively, compared to women, whose ranges were 52.58 to 585.88 ng/ml and 13.00 to 29.00 mAU/ml. For other biomarkers, the overall RIs were established as follows: alpha-fetoprotein (AFP) 0–6.75 ng/ml, carcinoembryonic antigen (CEA) 0–4.85 ng/ml, carbohydrate antigen15-3 (CA15-3) for females 0–22.00 U/ml, carbohydrate antigen19-9 (CA19-9) 0–28.10 U/ml, carbohydrate antigen125 (CA125) 0–20.96 U/ml, cytokeratin 19 fragment (CYFRA21-1) 0–4.66 U/ml, neuron-specific enolase (NSE) 0–19.41 ng/ml, total and free prostate-specific antigens (tPSA and fPSA) for males 0–5.26 ng/ml and 0–1.09 ng/ml. The RIs for all these biomarkers have been validated through our rigorous processes. Conclusion This study preliminarily established 95% RIs for an apparently healthy elderly population in Southwestern China. Using real-world data and an indirect method, simple and reliable RIs for an elderly population can be both established and verified, which are suitable for application in various clinical laboratories.

Introduction: Direct ways of establishing reference intervals for analytes are time-consuming and costly. Bhattacharya analysis is an indirect way to mathematically derive reference intervals from the results of analytes in a hospital database and is practically a simple and inexpensive alternative to direct methods. Methods: Data of serum uric acid, magnesium, and plasma homocysteine levels measured in the department of clinical biochemistry over 3 years were extracted from the hospital database along with the age, gender, and location of the patients. Bhattacharya analysis was performed by identifying underlying Gaussian distribution within the non-Gaussian distribution of the patient data by log transformation of the distribution of the data. Reference intervals for each of the analytes were calculated from the identified Gaussian distribution. Results: The reference interval for serum uric acid was 1.49–8.97 mg/dL in men and 2.13–6.14 in women, serum magnesium in adults was 1.19–3.21 mg/dL, and plasma homocysteine in adults was 4.6–21 μg/dL. Conclusion: Using Bhattacharya analysis, we were able to derive reference intervals for analytes from our hospital data.

Introduction Methods Results Conclusion Reticulocyte count and novel derived parameters provide insight into the effectiveness of erythropoiesis and may be useful tools in the classification and diagnosis of anemias. However, there is no standardisation, so we consider it necessary that each laboratory evaluates the parameters according to its own methodology and instrumentation and establishes its own reference ranges. Our aim was to establish the reference intervals (RIs) of reticulocyte profile provided by the Beckman Coulter DxH 900 haematological autoanalyzer in our reference population.One hundred and seventy‐five healthy adults (18 to 62 years) were included. Subjects were collected from the blood donation centre of the Hospital Clínico San Carlos (Madrid, Spain) upon informed consent. Whole blood was collected and assayed for 14 haematological parameters on the Beckman Coulter DxH 900 analyzer in the haematology laboratory of the Clinical Analysis Department. RIs were established as per Clinical and Laboratory Standards Institute EP28‐A3c guidelines using three different statistical approaches.RIs estimated using the non‐parametric method and the Harrell‐Davis bootstrap method were very similar. RIs estimated by the robust method were narrower. Gender partitioning was required for two haematological parameters (low haemoglobin density (LHD) and microcytic anaemia factor (MAF)). The rest of the parameters did not need to be partitioned according to Lahti's method.RIs have been established for 14 hematologic parameters of the reticulocyte profile for the Beckman Coulter DxH 900 haematology analyzer using a healthy cohort of adult subjects. [ABSTRACT FROM AUTHOR]

Evidence derived from laboratory medicine plays a pivotal role in the diagnosis, treatment monitoring, and prognosis of various diseases. Reference intervals (RIs) are indispensable tools for assessing test results. The accuracy of clinical decision-making relies directly on the appropriateness of RIs. With the increase in real-world studies and advances in computational power, there has been increased interest in establishing RIs using big data. This approach has demonstrated cost-effectiveness and applicability across diverse scenarios, thereby enhancing the overall suitability of the RI to a certain extent. However, challenges persist when tests results are influenced by age and sex. Reliance on a single RI or a grouping of RIs based on age and sex can lead to erroneous interpretation of results with significant implications for clinical decision-making. To address this issue, the development of next generation of reference interval models has arisen at an historic moment. Such models establish a curve relationship to derive continuously changing reference intervals for test results across different age and sex categories. By automatically selecting appropriate RIs based on the age and sex of patients during result interpretation, this approach facilitates clinical decision-making and enhances disease diagnosis/treatment as well as health management practices. Development of next-generation reference interval models use direct or indirect sampling techniques to select reference individuals and then employed curve fitting methods such as splines, polynomial regression and others to establish continuous models. In light of these studies, several observations can be made: Firstly, to date, limited interest has been shown in developing next-generation reference interval models, with only a few models currently available. Secondly, there are a wide range of methods and algorithms for constructing such models, and their diversity may lead to confusion. Thirdly, the process of constructing next-generation reference interval models can be complex, particularly when employing indirect sampling techniques. At present, normative documents pertaining to the development of next-generation reference interval models are lacking. In summary, this review aims to provide an overview of the current state of development of next-generation reference interval models by defining them, highlighting inherent advantages, and addressing existing challenges. It also describes the process, advanced algorithms for model building, the tools required and the diagnosis and validation of models. Additionally, a discussion on the prospects of utilizing big data for developing next-generation reference interval models is presented. The ultimate objective is to equip clinical laboratories with the theoretical framework and practical tools necessary for developing and optimizing next-generation reference interval models to establish next-generation reference intervals while enhancing the use of medical data resources to facilitate precision medicine. [ABSTRACT FROM AUTHOR]

Introduction: Cell population data (CPD) parameters may be putative biomarkers for the screening of various diseases including some infections and myelodysplastic syndrome. This study aimed to establish the age‐ and sex‐specific reference intervals (RIs) for the CPD parameters in the Korean population. Methods: The reference population for the RIs of CPD parameters comprised 124 856 subjects aged 20–99 years. CPD parameters were obtained from Sysmex XN‐2000 (Kobe, Japan) datasets from 17 health promotion centers in 13 South Korean cities. We determined significant partitions for age and sex, and calculated RIs according to Clinical and Laboratory Standards Institute C28‐A3 guidelines. Results: The side scattered light intensity in the neutrophil area and the lymphocyte area did not require sex‐related partitioning except in those over the age of 50, among whom the lower limit (LL) and upper limit (UL) were lower in females. However, the side scattered light distribution width in the lymphocyte area required age‐ and sex‐related partitioning, in which LL and UL were higher in females. The LL and UL of the fluorescent light distribution width were higher in males in the neutrophil area and higher in females in the lymphocyte area, but age‐related partitioning was not required. The forward scattered light intensity in the neutrophil area, lymphocyte area, and monocyte area did not require age‐related partitioning in males. Conclusion: This study has determined comprehensive age‐ and sex‐specific RIs for CPD parameters, which could help to prove the clinical significance of these parameters in the Sysmex XN‐2000. [ABSTRACT FROM AUTHOR]

Objective To establish the derived indicators from blood cell analysis of the elderly in Anning region of Yunnan province, lymphocyte to monocyte ratio (LMR), neutrophil to lymphocyte ratio (NLR), platelet to lymphocyte ratio (PLR) reference interval, Observed differences from multicenter surveys, To determine the necessity to establish this reference interval. Methods The analysis results of people above 60 years old for physical examinations in the information system of Anning First People’s Hospital from June 2022 to September 2022 were collected retrospectively. The biological reference interval for healthy elderly people in Anning City was established according to the indirect method in the international CLSI EP28-A3c guidelines. Results A total of 8 877 cases were included. Red blood cell count (RBC), hemoglobin (HGB), hematocrit (HCT), mean red blood cell hemoglobin concentration (MCHC), platelet count (PLT), and lymphocyte percentage (LYM%) decreased with age, and the difference between men and women was statistically significant ( P < 0.05) . Only the broadband coefficient of variation of red blood cell volume distribution (RDWCV) increased with age. White blood cell count (WBC), absolute value of neutrophils (NEU#), absolute value of eosinophils (EOS#), percentage of neutrophils (NEU%), percentage of eosinophils (EOS%), mean red cell volume (MCV), standard deviation of red blood cell volume distribution width (RDWSD), platelet volume distribution width (PDW) were statistically significant only between men and women (P < 0.05), while the remaining items were not significant by age and sex (P > 0.05). NLR increased with age, and men were significantly higher than women of the same age. Both LMR and PLR were higher in females than in males. Conclusion The results of WBC, RBC, HGB, PLT and HCT in the self-built reference interval were quite different from the reference interval of the multi-center survey. [ABSTRACT FROM AUTHOR]

Context The Roche prolactin immunoassay is used throughout the world. It reports higher values than the Siemens immunoassay but the manufacturer-defined reference intervals are similar. Patient results are often above the Roche upper limit but within the Siemens interval, causing diagnostic confusion. Objective Establish new reference intervals for the Roche and Siemens prolactin immunoassays. Methods We established new reference intervals for the Roche and Siemens immunoassays using 374 specimens from healthy outpatients. We performed chart review for unnecessary testing and treatment for 298 patients in a 6-month period with at least 1 Roche prolactin value above the manufacturer-defined upper limit and below our new upper limit. Results The new upper limit for the Roche assay was 37.8 ng/mL (females) and 22.8 ng/mL (males). The manufacturer-defined limits were 23.3 ng/mL and 15.2 ng/mL, respectively. New intervals for the Siemens assay matched the manufacturer. No cases of clinically significant pathophysiologic prolactin excess were identified in patients with values between the manufacturer-defined upper reference limit and our new Roche upper limit. Unnecessary further evaluation in these patients included 459 repeat prolactin measurements, 57 macroprolactin measurements, 39 magnetic resonance imaging studies, and 28 endocrine referrals. Eleven patients received dopamine agonists. The minimum cost of excess care using Medicare reimbursement rates was $34 134, with substantially higher amounts billed to patients and their insurance providers. Conclusion Adoption of new upper reference limits for the Roche prolactin assay of 37.8 ng/mL (females) and 22.8 ng/mL (males) would not delay diagnosis or necessary intervention in patients with clinically significant pituitary tumors but would reduce unnecessary evaluation in patients without pathophysiologic prolactin excess. [ABSTRACT FROM AUTHOR]

Background: The aim is to establish and verify reference intervals (RIs) for serum tumor markers for an apparently healthy elderly population in Southwestern China using an indirect method. Methods: Data from 35,635 apparently healthy elderly individuals aged 60 years and above were obtained in West China Hospital from April 2020 to December 2021. We utilized the Box-Cox conversion combined with the Tukey method to normalize the data and eliminate outliers. Subgroups are divided according to gender and age to examine the division of RIs. The Z-test was used to compare differences between groups, and 95% distribution RIs were calculated using a nonparametric method. Results: In the study, we observed that the RIs for serum ferritin and Des-γ-carboxy prothrombin (DCP) were wider for men, ranging from 64.18 to 865.80 ng/ml and 14.00 to 33.00 mAU/ml, respectively, compared to women, whose ranges were 52.58 to 585.88 ng/ml and 13.00 to 29.00 mAU/ml. For other biomarkers, the overall RIs were established as follows: alpha-fetoprotein (AFP) 0–6.75 ng/ml, carcinoembryonic antigen (CEA) 0–4.85 ng/ml, carbohydrate antigen15-3 (CA15-3) for females 0–22.00 U/ml, carbohydrate antigen19-9 (CA19-9) 0–28.10 U/ml, carbohydrate antigen125 (CA125) 0–20.96 U/ml, cytokeratin 19 fragment (CYFRA21-1) 0–4.66 U/ml, neuron-specific enolase (NSE) 0–19.41 ng/ml, total and free prostate-specific antigens (tPSA and fPSA) for males 0–5.26 ng/ml and 0–1.09 ng/ml. The RIs for all these biomarkers have been validated through our rigorous processes. Conclusion: This study preliminarily established 95% RIs for an apparently healthy elderly population in Southwestern China. Using real-world data and an indirect method, simple and reliable RIs for an elderly population can be both established and verified, which are suitable for application in various clinical laboratories. [ABSTRACT FROM AUTHOR]

Background: Initial evaluation of the hypothalamus–pituitary–thyroid axis is done by measuring serum free thyroxine (fT4) and thyrotropin concentrations. For correct interpretation of these measurements, reliable age-specific reference intervals (RIs) are fundamental. Since neonatal fT4 RIs conforming to the Clinical and Laboratory Standards Institute guidelines are not available for all assays, we set out to create literature-based uniform age-specific neonatal fT4 RIs that may be used for every assay. Methods: For meta-analysis of individual participant fT4 concentrations, we systematically searched MEDLINE and Embase (search date December 6, 2023; PROSPERO registration CRD42016041871). We searched for studies reporting fT4 concentrations in healthy term newborns aged 2–27 days, born to mothers without thyroid disease in iodine-sufficient regions. Authors were invited to supply data. Due to standardization differences between assays, data could not be combined for meta-analysis directly, and we attempted to normalize the data using two distinct methods. Results: We obtained 4206 fT4 concentrations from 20 studies that used 13 different assays from 6 manufacturers. First, we set out to normalize fT4 data using the mean and standard deviation of (assay-specific) adult RIs. fT4 concentrations were transformed into Z-scores, assuming a normal distribution. Using a linear mixed-effects model (LMM), we still found a significant difference between fT4 concentration across studies (p < 0.001), after this normalization. As a second approach, we normalized the fT4 concentrations using data from a method/assay comparison study. We used the relationship between the Cobas assay and the other assays as a reference point to convert all values to Cobas values. However, this method also failed to produce consistent results, with significant differences between the normalized data (LMM p < 0.001). Conclusions: We conclude that our attempts at normalizing fT4 assay results were unsuccessful. Confounders related to our unsuccessful analysis may be assay related and/or biological. These findings have significant implications for patient care, since relying on RIs from literature may result in erroneous interpretation of results. Therefore, we strongly recommend to establish local RIs for accurate interpretation of serum fT4 concentrations in neonates. [ABSTRACT FROM AUTHOR]

Background Elevated homocysteine (Hcy) level during pregnancy is positively associated with various gestational-specific diseases. However, there is no uniform standard for the reference interval (RI) of Hcy in pregnancy. Methods From January 2017 to January 2019, 14,530 singleton pregnant women registered at our institute were included for the establishment of trimester-specific RIs of Hcy with both the nonparametric approach and the indirect Hoffmann method, followed by pregnancy outcome association analysis conducted with logistic regression. Results The serum Hcy level in the nonpregnant group was significantly higher than that of pregnant women. A relatively decreased Hcy concentration was observed in the second trimester when compared with that of the first or third trimester. The direct RIs of Hcy in the first or third, and second trimesters were 4.6 to 8.0 mmol/L (merged) and 4.0 to 6.4 mmol/L, respectively, which showed no significant difference compared with the RI derived from the indirect Hoffmann method. In the subsequent risk analysis, the first trimester Hcy was found to be negatively associated with GDM development; whereas the third trimester Hcy conferred increased risk of postpartum hemorrhage after delivery. Conclusion Having established trimester-specific RIs, our study sheds light on the complicated roles of Hcy in pregnancy-related complications. [ABSTRACT FROM AUTHOR]

Monocyte distribution width (MDW) is a new biomarker used as an early indicator of sepsis (ESId). It is often aids in the identification of patients who may develop sepsis. This study aims to establish the MDW reference interval (RI) within the healthy population of blood donors using EDTA-K2 as anticoagulant. Many hospitals use this biomarker as a means of identifying patients who present to the hospital with sepsis. A total of 274 samples obtained from healthy donors were analyzed. MDW measurements were taken within 2 h post-extraction. The RI was estimated using various statistical methodologies, including the recommended CLSI EP28-A3c guideline, non-parametric and robust methods, along with the Harrell-Davis bootstrap method applied to the entire sample. The RI estimated through non-parametric method was 14.77 CI90 % (14.36–14.97)–21.13 CI90 % (20.89–21.68); RI using the robust method was 15.64–19.05 and RI using the Harrell-Davis bootstrap method was 14.73 CI90 % (14.53–14.92)–21.14 CI90 % (20.88–21.40). Based on clinical applicability, we recommend utilizing the RI derived from the non-parametric method, aligning with the CLSI recommendations. Furthermore, we consider that our results can be taken as a reference in other laboratories that serve a population similar to our study cohort. [ABSTRACT FROM AUTHOR]

Glomerular filtration rate (GFR) estimating equations based on rescaled serum creatinine (SCr/Q) have shown better performance, where Q represents the median SCr for age- and sex-specific healthy populations. However, there remains a scarcity of investigations in China to determine this value. We aimed to develop Chinese age- and sex-specific reference intervals (RIs) and Q-values for SCr and to validate the equations incorporating new Q-values. We included 117,345 adults from five centers for establishing RIs and Q-values, and 3,692 participants with reference GFR (rGFR, 99mTc-DTPA renal dynamic imaging measurement) for validation. Appropriate age partitioning was determined using the decision tree method. Lower and upper reference limits and medians were calculated using the refineR algorithm, and Q-values were determined accordingly. We evaluated the full age spectrum (FAS) and European Kidney Function Consortium (EKFC) equations incorporating different Q-values considering bias, precision (interquartile range, IQR), and accuracy (percentage of estimates within ±20 % [P20] and ±30 % [P30] of rGFR). RIs for males were: 18–79 years, 55.53–92.50 μmol/L; ≥80 years, 54.41–96.43 μmol/L. RIs for females were: 18–59 years, 40.42–69.73 μmol/L; 60–79 years, 41.16–73.69 μmol/L; ≥80 years, 46.50–73.20 μmol/L. Q-values were set at 73.82 μmol/L (0.84 mg/dL) for males and 53.80 μmol/L (0.61 mg/dL) for females. After validation, we found that the adjusted equations exhibit less bias, improved precision and accuracy, and increased agreement of GFR categories. We determined Chinese age- and sex-specific RIs and Q-values for SCr. The adjustable Q-values provide an effective alternative to obtain valid equations for estimating GFR. [ABSTRACT FROM AUTHOR]

Background and Objectives: Pregnancy introduces various interfering factors that, alongside individual variations, impact the assessment of thyroid function tests. This underscores the necessity of defining trimester-specific reference intervals for thyroid-stimulating hormone (TSH) levels. Differences in population characteristics, including ethnicity, socio-economic factors, iodine prophylaxis, and obesity, emphasize the need to establish trimester-specific TSH ranges for women of reproductive age in the respective region or center. The aim of the present study was to establish first- and second-trimester-specific reference intervals for TSH and free thyroxine (FT4) in a relevant pregnant population. Materials and Methods: A retrospective monocenter analysis utilized the electronic database of Ob/Gyn Hospital "Dr. Shterev", Sofia, Bulgaria. The analysis involved data from 497 pregnant and 250 non-pregnant women, all without evidence of thyroid dysfunction or a family history thereof, no indication of taking medication interfering with thyroid function, no evidence of levothyroxine treatment, and no history of sterility treatment. To establish the limits of the TSH reference range, the percentile method was applied using a bootstrapping procedure following the recommendations of the International Federation of Clinical Chemistry (IFCC). Results: Trimester-specific reference intervals for TSH and FT4 in our center were established as follows: first trimester—0.38–2.91 mU/L, FT4-12.18–19.48 pmol/L; second trimester—0.72–4.22 mIU/L and 9.64–17.39 pmol/L, respectively. We also established the normal reference range for the non-pregnant control group, which is similar to that applicable in our laboratory. Conclusions: Our results differ from the fixed limits recommended by the American Thyroid Association, European Thyroid Association, and Endocrine Society Guidelines. Following the relevant established intervals would significantly impact timely diagnosis and therapy requirements for a substantial proportion of pregnant women. [ABSTRACT FROM AUTHOR]

Clustering algorithms are usually iterative procedures. In particular, when the clustering algorithm aims to optimise an objective function like in k-means clustering or Gaussian mixture models, iterative heuristics are required due to the high non-linearity of the objective function. This implies higher computational costs and the risk of finding only a local optimum and not the global optimum of the objective function. In this paper, we demonstrate that in the case of one-dimensional clustering with one main and one noise cluster, one can formulate an objective function, which permits a closed-form solution with no need for an iteration scheme and the guarantee of finding the global optimum. We demonstrate how such an algorithm can be applied in the context of laboratory medicine as a method to estimate reference intervals that represent the range of "normal" values. [ABSTRACT FROM AUTHOR]

The reference intervals and median values of serum vitamin B12 level in blood from patients among the Latvian population were established for different age groups with a two-year step using data for a large number of patients, accumulated in E. Gulbis Laboratory in Latvia. The data represents the general population of Latvia. An indirect in silico method, developed in E. Gulbis laboratory for determination of serum vitamin B12 blood level reference intervals, was used. Strong elevation of serum vitamin B12 blood level was observed in children who were between 2 and 10 years old. The paper discusses the serum vitamin B12 values for children and a different serum vitamin B12 reference interval for young children is suggested. [ABSTRACT FROM AUTHOR]

Chronic kidney disease (CKD) is common in older rabbits. The renal biomarkers blood urea and creatinine can be insensitive as indicators of renal disease in rabbits. Symmetric dimethylarginine (SDMA) has been shown to be an earlier and more sensitive biomarker for the assessment of glomerular filtration rate and the evaluation of CKD in several animal species. An immunoassay for SDMA has been validated in a number of species. The purpose of this study was to validate the SDMA immunoassay for rabbit serum and plasma and to determine the normal rabbit reference interval (RI) for SDMA. Clinically healthy rabbits (n = 167) between 5 months and 8 years of age, of any breed or sex, participated in the study. Heparinized plasma or serum was collected for clinical chemistry and used for assay validation. Analytical validation of the SDMA immunoassay for rabbit serum and plasma was performed and included assessment of assay accuracy, precision, analytical sensitivity, linearity, interference testing, and plasma/serum bias. The SDMA reference interval (RI) was determined. The SDMA immunoassay met all set quality requirements assessed in analytical validation. The RI for SDMA was determined to be between 4–18 µg/dL. The SDMA immunoassay demonstrated acceptable performance in both rabbit serum and heparinized plasma as determined by the validation criteria. The utility of SDMA as a biomarker of renal disease in rabbits has not been determined yet. [ABSTRACT FROM AUTHOR]

Reference intervals play an important role in medicine, for instance, for the interpretation of blood test results. They are defined as the central 95% values of a healthy population and are often stratified by sex and age. In recent years, so-called indirect methods for the computation and validation of reference intervals have gained importance. Indirect methods use all values from a laboratory, including the pathological cases, and try to identify the healthy sub-population in the mixture of values. This is only possible under certain model assumptions, i.e., that the majority of the values represent non-pathological values and that the non-pathological values follow a normal distribution after a suitable transformation, commonly a Box–Cox transformation, rendering the parameter λ of the Box–Cox transformation as a nuisance parameter for the estimation of the reference interval. Although indirect methods put high effort on the estimation of λ, they come to very different estimates for λ, even though the estimated reference intervals are quite coherent. Our theoretical considerations and Monte-Carlo simulations show that overestimating λ can lead to intolerable deviations of the reference interval estimates, whereas λ=0 produces usually acceptable estimates. For λ close to 1, its estimate has limited influence on the estimate for the reference interval, and with reasonable sample sizes, the uncertainty for the λ-estimate remains quite high.

Abstract Background White blood cell (WBC) count increases during pregnancy, necessitating reliable reference intervals for assessing infections and pregnancy-related complications. This study aimed to establish comprehensive reference intervals for WBC counts during pregnancy. Methods The analysis included 17,737 pregnant women, with weekly WBC count measurements from pre-pregnancy to postpartum. A threshold linear regression model determined reference intervals, while Harris and Boyd’s test partitioned the intervals. Results WBC count exhibited a significant increase during pregnancy, characterized by a rapid rise before 7 weeks of gestation, followed by a plateau. Neutrophils primarily drove this increase, showing a similar pattern. The threshold regression model and Harris and Boyd’s test supported partitioned reference intervals for WBC counts: 4.0–10.0 × 10^9/L for = 6 weeks of gestation. These reference intervals identified pregnant women with high WBC counts, who had a higher incidence of pregnancy-related complications including placenta previa, oligohydramnios, secondary uterine inertia, and intrauterine growth restriction. Conclusion This study establishes comprehensive reference intervals for WBC counts during pregnancy. Monitoring WBC counts is clinically relevant, as elevated levels are associated with an increased risk of infection and pregnancy-related complications.

The interpretation of laboratory data is a comparative procedure. Physicians typically need reference values to compare patients’ laboratory data for clinical decisions. Therefore, establishing reliable reference data is essential for accurate diagnosis and patient monitoring. Human metabolism is a dynamic process. Various types of systematic and random fluctuations in the concentration/activity of biomolecules are observed in response to internal and external factors. In the human body, several biomolecules are under the influence of physiological rhythms and are therefore subject to ultradian, circadian and infradian fluctuations. In addition, most biomolecules are also characterized by random biological variations, which are referred to as biological fluctuations between subjects and within subjects/individuals. In routine practice, reference intervals based on population data are used, which by nature are not designed to capture physiological rhythms and random biological variations. To ensure safe and appropriate interpretation of patient laboratory data, reference intervals should be personalized and estimated using individual data in accordance with systematic and random variations. In this opinion paper, we outline (i) the main variations that contribute to the generation of personalized reference intervals (prRIs), (ii) the theoretical background of prRIs and (iii) propose new methods on how to harmonize prRIs with the systematic and random variations observed in metabolic activity, based on individuals’ demography. [ABSTRACT FROM AUTHOR]

Objectives To evaluate the real-world performance and reference intervals of the Binding Site Freelite serum free light chain (SFLC) assay (Thermo Fisher Scientific), a global standard for diagnosis, prognostication, and response assessment for monoclonal gammopathies. Methods An informatics-based approach was used to retrospectively evaluate concordance between SFLC and the orthogonal Sebia HYDRASYS immunofixation assay results in a large clinical data set consecutively reported between 2010 and 2020. Results Among patients with monoclonal-negative results by both SFLC and Sebia HYDRASYS immunofixation assays, 25% (1226/5057) had κ/λ ratios (KLRs) outside the manufacturer-defined and International Myeloma Working Group–cited normal reference interval of 0.26 to 1.65. These results were consistent over the study period and were not affected by sex, age, impaired kidney function, or assay antisera lot variation. Assay drift, in addition to other potential factors, affected the KLR distribution. Using International Statistical Classification of Diseases (ICD) codes, kidney function data, and the central 95% of KLR values generated on the Optilite platform (Thermo Fisher Scientific), we derived a new reference interval of 0.67 to 2.13, reducing the KLR false-positive rate to 8%. However, normal KLR persisted among 16% (14/85) of samples with free λ chains by immunofixation, warranting caution during interpretation. Conclusions Our analysis indicated that revision of Freelite SFLC reference intervals improves assay interpretation and should prompt reconsideration of Freelite reference intervals worldwide. [ABSTRACT FROM AUTHOR]

Reference intervals play an important role in medicine, for instance, for the interpretation of blood test results. They are defined as the central 95% values of a healthy population and are often stratified by sex and age. In recent years, so-called indirect methods for the computation and validation of reference intervals have gained importance. Indirect methods use all values from a laboratory, including the pathological cases, and try to identify the healthy sub-population in the mixture of values. This is only possible under certain model assumptions, i.e., that the majority of the values represent non-pathological values and that the non-pathological values follow a normal distribution after a suitable transformation, commonly a Box–Cox transformation, rendering the parameter λ of the Box–Cox transformation as a nuisance parameter for the estimation of the reference interval. Although indirect methods put high effort on the estimation of λ , they come to very different estimates for λ , even though the estimated reference intervals are quite coherent. Our theoretical considerations and Monte-Carlo simulations show that overestimating λ can lead to intolerable deviations of the reference interval estimates, whereas λ = 0 produces usually acceptable estimates. For λ close to 1, its estimate has limited influence on the estimate for the reference interval, and with reasonable sample sizes, the uncertainty for the λ -estimate remains quite high. [ABSTRACT FROM AUTHOR]

Bone-turnover marker (BTM) measurements in the blood or urine reflect the bone-remodeling rate and may be useful for studying and clinically managing metabolic bone diseases. Substantial evidence supporting the diagnostic use of BTMs has accumulated in recent years, together with the publication of several guidelines. Most clinical trials and observational and reference-interval studies have been performed in the Northern Hemisphere and have mainly involved Caucasian populations. This review focuses on the available data for populations from the Asia-Pacific region and offers guidance for using BTMs as diagnostic biomarkers in these populations. The procollagen I N-terminal propeptide and ß-isomerized C-terminal telopeptide of type-I collagen (measured in plasma) are reference BTMs used for investigating osteoporosis in clinical settings. Premenopausal reference intervals (established for use with Asia-Pacific populations) and reference change values and treatment targets (used to monitor osteoporosis treatment) help guide the management of osteoporosis. Measuring BTMs that are not affected by renal failure, such as the bone-specific isoenzyme alkaline phosphatase and tartrate-resistant acid phosphatase 5b, may be advantageous for patients with advanced chronic kidney disease. Further studies of the use of BTMs in individuals with metabolic bone disease, coupled with the harmonization of commercial assays to provide equivalent results, will further enhance their clinical applications. [ABSTRACT FROM AUTHOR]

Testing of serum-free light chains kappa (κ) and lambda (λ), along with ratio (FLCR) is essential for the diagnosis and management of monoclonal gammopathies. Accurate clinical diagnosis depends upon appropriate local population reference intervals (RIs). This study examined the Saudi population for serum-free light chains and other immunoglobulins to establish RIs and to explore variations in the test results by using the International Federation for Clinical Chemistry and Laboratory Medicine's global protocol for harmonized implementation of RI study. A total of 180 healthy Saudi adults were recruited. All serum samples were assayed using the Freelite reagents from the Binding Site. The variation in reference values attributable to sex, age, BMI, and region was calculated by ANOVA as a standard deviation ratio (SDR). The RIs for the FLCR were derived by the parametric method and validated by using samples from patients with hypo- and hypergammaglobulinemia. The new RIs for free κ and FLCR were shifted to a higher side from the manufacturer-adapted RIs. Based on the SDR cutoff value (>0.4), between-sex partition RIs were not required for all analytes except IgM. Validation using patients with hypo- or hypergammaglobulinemia and without multiple myeloma, was all within the new RI. BMI, smoking, and exercise were not relevant sources of variation for any analyte. Locally derived RIs for free light chains and immunoglobulins analytes specific for Saudis were established after careful consideration of various factors. These RIs were more reliable than those provided as guidance by the manufacturer, or from other countries, for appropriate classification and prediction of disease progression for Saudi patients. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Medical Equipment Journal is the property of Chinese Medical Equipment Journal Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: White blood cell (WBC) count increases during pregnancy, necessitating reliable reference intervals for assessing infections and pregnancy-related complications. This study aimed to establish comprehensive reference intervals for WBC counts during pregnancy. Methods: The analysis included 17,737 pregnant women, with weekly WBC count measurements from pre-pregnancy to postpartum. A threshold linear regression model determined reference intervals, while Harris and Boyd's test partitioned the intervals. Results: WBC count exhibited a significant increase during pregnancy, characterized by a rapid rise before 7 weeks of gestation, followed by a plateau. Neutrophils primarily drove this increase, showing a similar pattern. The threshold regression model and Harris and Boyd's test supported partitioned reference intervals for WBC counts: 4.0–10.0 × 10^9/L for < = 2 weeks, 4.7–11.9 × 10^9/L for 3–5 weeks, and 5.7–14.4 × 10^9/L for > = 6 weeks of gestation. These reference intervals identified pregnant women with high WBC counts, who had a higher incidence of pregnancy-related complications including placenta previa, oligohydramnios, secondary uterine inertia, and intrauterine growth restriction. Conclusion: This study establishes comprehensive reference intervals for WBC counts during pregnancy. Monitoring WBC counts is clinically relevant, as elevated levels are associated with an increased risk of infection and pregnancy-related complications. [ABSTRACT FROM AUTHOR]

Simple Summary: Vitamin D deficiency and toxicity are common and well-recognized conditions in dogs. The metabolite 25-hydroxyvitamin D3 is the main endogenous biomarker for the evaluation of vitamin D3 status. In this study, we developed a simple analytical method for 25-hydroxyvitamin D3 quantification in canine serum. The method was validated following the current European guidelines and yielded satisfactory results, representing a new tool for supporting clinicians in the correct diagnosis and monitoring of vitamin D3 status in dogs. Several studies have shown the importance of vitamin D3 supplementation in small animals. In dogs, a low vitamin D3 status is associated not only with bone metabolism but also with different kinds of disorders, such as congestive heart failure, gastrointestinal diseases, chronic kidney diseases, and some types of cancer. However, it is crucial to maintain balance and monitor the introduction of this essential nutrient through the diet because over-supplementation can result in toxicity. Due to the clinical importance of assessing the vitamin D3 status in small animal patients, a quick, simple, and highly performing analytical method for its measurement is needed. In this study, we describe the development of a novel liquid chromatography–tandem mass spectrometry method for 25-hydroxyvitamin D3 quantification in canine serum. The approach was successfully validated following current European guidelines, proving excellent linearity (R2 always ≥0.996), accuracy (always within ±13%) and precision (always <10%). The application of the validated approach to samples collected from 40 healthy dogs made possible the definition of a reliable reference interval for 25-hydroxyvitamin D3, the main biomarker of vitamin D3. In addition, variations below 5% in the results obtained quantifying the same samples using a water-based calibration curve demonstrated that a surrogate matrix may be used without affecting data accuracy. Thanks to its simplicity, the proposed technique represents a useful tool for supporting clinical routine and investigating correlations between serum concentrations of this metabolite and multiple diseases. Additionally, it could enable the monitoring of supplementation in small animal patients in veterinary clinical practice. [ABSTRACT FROM AUTHOR]

Objective Classic androgens such as dehydroepiandrosterone, androstenedione, and testosterone are generally measured for diagnosis and treatment monitoring in children and adolescents with hyperandrogenism, as can occur in congenital adrenal hyperplasia, premature pubarche, or polycystic ovarian syndrome. However, adrenally-derived 11-oxygenated androgens also contribute to the androgen pool and should therefore be considered in clinical management. Nevertheless, paediatric reference intervals are lacking. Therefore, we developed a serum assay to establish reference intervals for four 11-oxygenated androgens in addition to four classic androgens. Design Reference interval study for serum 11-oxygenated androgens in children. Methods We developed and validated a sensitive liquid chromatography-tandem mass spectrometry assay and quantified eight serum androgens, including four 11-oxygenated androgens, in serum of 256 healthy children (aged 0-17 years old). An age-dependency for all androgens was observed, and therefore we divided the cohort based on age (prepubertal [ n = 133; 94 boys, 39 girls] and pubertal [ n = 123; 52 boys, 71 girls]) to compute reference intervals (2.5th-97.5th percentiles). Results In the prepubertal group, there was no significant sex-difference for any of the measured androgens. In the pubertal group, androstenedione, testosterone, and dihydrotestosterone showed a significant difference between boys and girls. In contrast, adrenal androgens dehydroepiandrosterone, 11-hydroxyandrostenedione, 11-ketoandrostenedione, 11-hydroxytestosterone, and 11-ketotestosterone did not. Conclusions We developed and validated an assay for 11-oxygenated androgens, in addition to four classic androgens and established reference intervals. This enables a comprehensive evaluation of serum androgen status in children with clinical symptoms of hyperandrogenism. [ABSTRACT FROM AUTHOR]

Background: Growing evidence shows the undisputable role of non-HDL-C and remnant cholesterol (remnant-C) in cardiovascular disease (CVD) risk assessment and treatment. However, the reference interval (RI) for these lipid parameters is not readily available. The aim of the present investigation was to determine the age and sex-specific RIs for non-HDL-C and remnant-C as well as other lipid parameters among a healthy population in southern Iran. We also report the RI of lipid parameters in rural and urban residents, smokers and post-menopausal women. Methods: Among 14 063 participants of Bandare Kong and Fasa cohort studies, 792 healthy subjects (205 men and 578 women) aged 35-70 years were selected. Fasting blood samples were used for determination of total cholesterol (TC), triglycerides (TG) and HDL-C using colorimetric methods. Non-HDL-C and remnant-C were calculated using the valid formula. The 2.5th and 97.5th percentiles were calculated and considered as RI. Results: In the total population (n = 792, age 35-70), RIs for non-HDL-C and remnant-C was 74.0-206.8 and 8.0-52.7 mg/dL, respectively. Age (35-44 and ≥ 45 years) and gender-specific RIs for serum non-HDL-C and remnant-C were determined. Remnant-C and non-HDL-C level were different between sex and age categories. The mean value of all lipid parameters except HDL-C was higher in men, urban residents, subject with age ≥ 45 years and smokers. Conclusion: This is the first study in which the RIs for non-HDL-C and remnant-C in southern Iran are reported. This may help physicians to conveniently use these lipid parameters for patient care and better cardiovascular risk assessment. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to establish the reference intervals of Cyfra21-1 and CEA for the local screening populations using a chemiluminescence method. Methods: A total of 4845 healthy adults and 190 lung cancer patients were included from the First Hospital of Hebei Medical University. The levels of Cyfra21-1 and CEA were measured to establish the local reference intervals. Results: The upper limit reference intervals for Cyfra21-1 and CEA were determined as 3.19 ng/ml and 3.13 ng/ml, respectively. Notably, both Cyfra21-1 and CEA levels were found to be higher in males than in females. Additionally, both biomarkers showed an increasing trend with age.In terms of diagnostic efficacy, the receiver operating characteristic (ROC) curve areas for Cyfra21-1, CEA, and their combination in lung cancer were 0.86, 0.73, and 0.91, respectively. Conclusion: Our study revealed that the reference intervals of Cyfra21-1 and CEA in the local population differed from the established reference intervals. Furthermore, both biomarkers exhibited gender-dependent variations and demonstrated a positive correlation with age. Combining the two biomarkers showed potential for improving the diagnosis rate of lung cancer.

BackgroundReference intervals are an important method tool for identifying abnormal laboratory test results. Complete blood count reference values are useful to interpret complete blood count (CBC) results and make clinical decisions, but these values have not been established for geriatrics in Asella town. Therefore, this study aimed to establish reference intervals (RIs) for complete blood count (CBC) parameters from geriatric participants/subjects in Asella town, Southeast Ethiopia.MethodsA community-based cross-sectional study was conducted from December 2019 to May 2020. An interviewer-administered questionnaire was used to collect data on sociodemography and other characteristics from 342 eligible geriatric participants. Weight, height, and vital signs were measured, and 8 mL of blood sample was collected. Screening tests such as HIV, HBsAg, HCV, syphilis, stool examination, and urinalysis were performed. The hematological parameter was measured using a Sysmex kx-21 hematology analyzer. The data were analyzed using SPSS version 21 software. The non-parametric independent Kruskal–Wallis test and Wilcoxon rank-sum test (Mann–Whitney U test) were used to compare the parameters between age groups and genders. The 97.5 and 2.5th percentile were the upper and lower reference limit for the population.ResultsAccording to the study’s findings, the reference intervals of red blood cell, white blood cell, platelet count, hemoglobin (HGB), and hematocrit (HCT) in male geriatrics were 3.8–5.85 × 1012/L, 3.1–9.66 × 109/L, 115.8–353 × 109/L, 12.4–17.76 g/dL, and 35.06–50.2%, respectively. The respective values for women were 3.94–5.48 × 1012/L, 3.13–8.4 × 109/L, 137.5–406 × 109/L, 12.5–16.4 g/dL, and 36.09–48.2%. Most of the hematological parameters showed significant differences between the two genders (p value

Objective To establish a reference intervals (RIs) of serum squamous cell carcinoma antigen(SCC-Ag) in healthy population in Nanning region and provide clinical evidence to support diagnosis and prognosis of squamous cell carcinoma. Methods A total of 10 197 reference individuals who joined a routine physical examination in the Health Management Center of Guangxi International Zhuang Medical Hospital from March 2019 to December 2021 were collected. The level of serum SCC-Ag was detected by chemiluminescence microparticle immunoassay. The Mann-Whitney U test was applied to compare the differences in serum SCC level between genders or adjacent age groups. The unilateral 95th percentile determined the upper limit of the RIs by the nonparametric method. Another 1 035 healthy subjects with the same conditions as the reference population were selected for refer- ence validation. Results The serum SCC-Ag level showed a skewed distribution (Z=0.08, P＜0.05). The serum SCC-Ag level of males was considerably higher than that of females. There was significant difference in serum SCC-Ag level between males aged 18-30 and 31-40, 51-60 and 61-90 (P＜0.05). There was significant difference in serum SCC-Ag level between females aged 18-30 and 31-40, 31-40 and 41-50, 51-60 and 61-90 (P＜0.05). The reference intervals of serum SCC-Ag was as follows: 0-1.64 ng/mL for males and females aged 18-30 years; 0-1.57 ng/mL and 0-1.70 ng/mL for males aged 31-60 years and 61-90 years, respectively; 0-1.50 ng/mL, 0-1.52 ng/mL and 0-1.42 ng/mL for females aged 31-40 years, 41-60 years and 61-90 years, respectively. Conclusions The RIs of serum SCC-Ag in healthy population in the Nanning region are successfully established according to different genders and ages.

Abstract Background Pregnancy has major effects that make hematology parameters outside of normal reference ranges. Therefore, we conducted this study to establish reference intervals for Vietnamese pregnant women. Methods From June 2023 to Augst 2023, blood samples from 879 eligible pregnant women were run on DxH 900 hematology analyzer and ACL TOP 550 coagulation analyzer. The tested parameters are prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen (FIB), white blood cell (WBC) and its differentials (neutrophils, lymphocytes, monocytes, eosinophils and basophils), red blood cell (RBC), hemoglobin (HGB), hematocrit (HCT), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), RBC distribution width (RDW), RBC distribution width standard deviation (RDW-SD), platelet count (PLT), mean platelet volume (MPV). A non-parametric method was used to establish the 2.5th and 97.5th percentile reference intervals. Results PT, APTT decrease but fibrinogen increases during pregnancy. Physiological adaptations of pregnancy result in a decrease in RBC count, but an increase in WBC count and no changes in platelet count. The reference intervals for PT (seconds), APTT (seconds), fibrinogen (mg/dL), in the first trimester were 10.30–12.88, 25.40–35.46, 280.28–559.00, in the second trimester were 9.80–11.66, 24.05–33.23, 347.75–593.35, in the third trimester were 9.60–11.40, 23.40–31.80, 330.28–628.56, respectively. The reference intervals for main hematology parameters which are WBC (× 109/L), RBC (× 1012/L), HGB (g/dL), HCT (%), PLT (× 109/L) in the first trimester were 6.33–15.24, 3.73–5.32, 10.33–13.95, 32.22–42.29, 169.66–413.88, in the second trimester were 6.99–15.55, 3.33–4.98, 9.71–13.17, 30.26–40.07, 172.34–372.19, in the third trimester were 6.22–14.14, 3.54–4.98, 9.80–13.97, 31.11–42.70, 151.30–417.14, respectively. Conclusions Most established referenced intervals from each trimester differ from other trimesters. These trimester-specific reference ranges for Vietnamese pregnant women will aid clinicians in entepreting parameters and help other laboratories adopt these ranges after validating. Trial registration This study is registered at www.clinicaltrials.gov as NCT05929326.

Serum erythropoietin (sEPO) is an initial screening tool for distinguishing polycythemia vera (PV) from secondary erythrocytosis (SE), but defining ‘subnormal’ sEPO levels for PV diagnosis remains contentious, complicating its clinical utility. This study compares the diagnostic performance of sEPO across established subnormal limits, including reference interval (RI), clinical decision limit (CDL), and functional reference limit. sEPO levels were analyzed in 393 healthy donors (HDs) and 90 patients (41 PV and 49 SE), who underwent bone marrow biopsy and genetic tests due to erythrocytosis. The RI (2.5–97.5 percentile from HDs) of sEPO was 5.3–26.3 IU/L. A CDL of 3.1 IU/L, determined by ROC analysis in erythrocytosis patients, had a sensitivity of 80.5% and specificity of 87.8% for diagnosing PV. A functional reference limit of 7.0 IU/L, estimated based on the relationship between sEPO and hemoglobin, hematocrit, and WBC, increased sensitivity to 97.6% but decreased specificity to 46.7%. Using 5.3 IU/L as a ‘subnormal’ limit identified all three JAK2-negative PV cases, increasing the sensitivity and negative predictive value to 97.6% and 97.0%, respectively. Combining the RI, CDL, and functional reference limit may improve PV diagnostic accuracy.

Some trace elements are essential for the health of vertebrates, but little is known about their function, the amounts required, and the factors influencing their metabolism in tortoises. The aim of this study was therefore to measure trace elements (chromium (Cr), cobalt (Co), copper (Cu), iron (Fe), magnesium (Mg), manganese (Mn), molybdenum (Mo), selenium (Se), zinc (Zn)) in heparinized blood plasma of Hermann’s tortoises (Testudo hermanni) (n = 520) from March to September 2022 using inductively coupled plasma mass spectrometry (ICP-MS) and to establish specific reference intervals. Additionally, the influence of sex, season, and region of sample collection on the measured values were evaluated. Significant (p ≤ 0.05) sex-specific differences were found for Cu, Mg, and Mn; seasonal differences were found for Cr, Cu, Mn, Mo, and Se; and the region in which the tortoises were kept significantly impacted Cr, Cu, Fe, Mg, Mo, and Se levels. The results show that all of these factors should be consider when establishing and interpreting blood trace element levels in tortoises.

Background/Objectives: We present a software package called reflimR (Version 1.0.6), which enables rapid and transparent verification of reference intervals from routine laboratory measurements. Our method makes it easy to compare the results with specified target values and facilitates the interpretation of deviations using traffic light colors. Methods: The algorithm includes three procedural steps: (a) definition of an appropriate distribution model, based on Bowley’s quartile skewness, (b) iterative truncation, based on a modified boxplot method to obtain the central 95% of presumably inconspicuous results, and (c) extrapolation of reference limits from a truncated normal quantile–quantile plot. Results: All algorithms have been combined into one consolidated library, which can be called in the R environment with a single command reflim (x). Using an example dataset included in the package, we demonstrate that our method can be applied to mixed data containing a substantial proportion of pathological values. It leads to similar results as the direct guideline approach as well as the more sophisticated indirect refineR software package. As compared to the latter, reflimR works much faster and needs smaller datasets for robust estimates. For the interpretation of the results, we present an intuitive color scheme based on tolerance ranges (permissible uncertainty of laboratory results). We show that a relatively high number of published reference limits require careful reevaluation. Conclusions: The reflimR package closes the gap between direct guideline methods and the more sophisticated indirect refineR method. We recommend reflimR for the rapid routine verification of large amounts of reference limits and refineR for a careful analysis of unclear or doubtful results from this check.

Background: Transthoracic echocardiography represents the main noninvasive technique for evaluating cardiac morphology and function in dogs. In dogs with particular somatotypes, such as brachymorphic dogs, breed-specific echocardiographic values are needed for a proper echocardiographic interpretation. Nowadays, the Pug represents one of the most popular brachymorphic canine breeds worldwide. However, data on echocardiographic measurements in this breed are currently limited. Aim: We aimed to determine echocardiographic values in a population of apparently healthy Pugs, and to assess the possible effects of body weight (BW), age, and sex on selected echocardiographic variables, with particular emphasis on those related to the left-sided cardiac chambers. Methods: Apparently healthy Pugs underwent a full physical examination, a 1-minute six-lead electrocardiogram, and a complete transthoracic echocardiography. Twenty-four echocardiographic variables were measured by combining M-mode, two-dimensional and Doppler modalities, and relative values were determined by applying the statistical procedures recommended by the Clinical and Laboratory Standards Institute. Moreover, the effect of selected demographic variables on echocardiographic measurements was tested using a linear mixed model. Results: The investigation included 86 Pugs. Echocardiographic values were provided for each variable and compared with previous veterinary literature. A statistically significant effect of BW, age, and sex was documented for several of the tested variables. Doppler examination demonstrated a trivial pulmonary regurgitation in 24/86 (27.9%) Pugs. Moreover, a persistent left cranial vena cava was suspected in 4/86 (4.7%) dogs. Conclusion: Echocardiographic features of the Pug were addressed and echocardiographic values were made available for clinical use. Because our findings were obtained using a standardized echocardiographic analysis in a population of 86 healthy Pugs, they may act as a reliable guide for an accurate echocardiographic interpretation in this breed. [ABSTRACT FROM AUTHOR]

To establish a reference intervals (RIs) of serum squamous cell carcinoma antigen (SCC- Ag) in healthy population in Nanning region and provide clinical evidence to support diagnosis and prognosis of squamous cell carcinoma. Methods A total of 10 197 reference individuals who joined a routine physical examination in the Health Management Center of Guangxi International Zhuang Medical Hospital from March 2019 to December 2021 were collected. The level of serum SCC-Ag was detected by chemiluminescence microparticle immunoassay. The Mann-Whitney U test was applied to compare the differences in serum SCC level between genders or adjacent age groups. The unilateral 95th percentile determined the upper limit of the RIs by the nonparametric method. Another 1 035 healthy subjects with the same conditions as the reference population were selected for reference validation. Results The serum SCC-Ag level showed a skewed distribution (Z=0.08, P<0.05). The serum SCC-Ag level of males was considerably higher than that of females. There was significant difference in serum SCC-Ag level between males aged 18-30 and 31-40, 51-60 and 61-90 (P<0.05). There was significant difference in serum SCC-Ag level between females aged 18-30 and 31-40, 31-40 and 41-50, 51-60 and 61- 90 (P<0.05). The reference intervals of serum SCC-Ag was as follows: 0-1.64 ng/ml. for males and females aged 18-30 years; 0-1.57 ng/ml. and 0-1.70 ng/ml. for males aged 31-60 years and 61-90 years, respec- tively; 0-1.50 ng/ml., 0-1.52 ng/ml. and 0-1.42 ng/ml for females aged 31-40 years, 41-60 years and 61-90 years, respectively. Conclusions The RIs of serum SCC-Ag in healthy population in the Nanning region are successfully established according to different genders and ages. [ABSTRACT FROM AUTHOR]