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Suppression of tumorigenicity 2 (ST2) has important cardiovascular prognostic value in community patients; however, previous analyses have utilized non-sex specific cut-off values. We assessed whether sex-specific ST2 cut-off values would improve the prognostic utility of ST2 in the asymptomatic community.A total of 2042 participants underwent clinical assessment and echocardiographic evaluation. Baseline measurements of high sensitivity troponin, natriuretic peptides and ST2 were obtained in 1681 individuals. ST2, cardiac biomarkers and associated co-morbidities were evaluated by sex-specific ST2 quartile analysis. ST2 concentrations were also analysed as dichotomous variables defined as being above the sex-specific cut-off for each the outcomes of heart failure (HF), major adverse cardiac event (MACE) and mortality.Median ST2 concentration was 29.4 ng/mL in male subjects and 24.1 ng/mL in female subjects. Higher ST2 concentrations were associated with incident HF (These data suggest that sex-specific cut-offs, greater than non-sex specific cut-offs, significantly impact the prognostic value of the biomarker ST2 in the asymptomatic community cohort.Clinical SignificanceSuppression of tumorigenicity 2 (ST2) is a biomarker which has known associations with heart failure (HF), major adverse cardiac events (MACEs) and mortality in the general population.Recent data support the concept of sex-specific cut off values and individualized approaches based on sex to predict cardiovascular disease. Given the difference in pathobiology between the sexes, the fact that such approaches improve risk stratification is understandable. Thus, when sex-specific treatments are developed, this may similarly lead to improved outcomes.The use of sex-specific ST2 cut-off values significantly improved the prognostic value in predicting HF, MACE, and mortality in an asymptomatic community. This prognostication was particularly strong for HF with preserved ejection fraction and remained clinically significant following adjustment for cardiac co-morbidities and other traditional cardiac biomarkers (NTproBNP and hscTnI).

Background Concerns exist regarding how the 99th percentile upper reference limit (URL) of cardiac troponin (cTn) is determined and whether it should be derived from normal healthy individuals. Content The 99th percentile URL of cTn is an important criterion to standardize the diagnosis of myocardial infarction (MI) for clinical, research, and regulatory purposes. Statistical heterogeneity in its calculation exists but recommendations have been proposed. Some negativity has resulted from the fact that with some high-sensitivity (hs) cTn assays, a greater number of increases above the 99th percentile are observed when transitioning from a contemporary assay. Increases reflect acute or chronic myocardial injury and provide valuable diagnostic and prognostic information. The etiology of increases can sometimes be difficult to determine, making a specific treatment approach challenging. For those reasons, some advocate higher cutoff concentrations. This approach can contribute to missed diagnoses. Contrary to claims, neither clinical or laboratory guidelines have shifted away from the 99th percentile. To support the diagnosis of acute MI, the 99th percentile URL remains the best-established approach given the absence of cTn assay standardization. Importantly, risk stratification algorithms using hs-cTn assays predict the possibility of MI diagnoses established using the 99th percentile. Summary The 99th percentile of cTn remains the best-established criterion for the diagnosis of acute MI. While not perfect, it is analytically and clinically evidence-based. Until there are robust data to suggest some other approach, staying with the 99th percentile, a threshold that has served the field well for the past 20 years, appears prudent.

Background and objectives Glomerular hyperfiltration has been considered to be a contributing factor to the development of diabetic kidney disease (DKD). To address this issue, we analyzed GFR follow-up data on participants with type 1 diabetes undergoing 125 I-iothalamate clearance on entry into the Diabetes Control and Complications Trial (DCCT)/Epidemiology of Diabetes Interventions and Complications study. Design, setting, participants, & measurements This was a cohort study of DCCT participants with type 1 diabetes who underwent an 125 I-iothalamate clearance (iGFR) at DCCT baseline. Presence of hyperfiltration was defined as iGFR levels ≥140 ml/min per 1.73 m 2 , with secondary thresholds of 130 or 150 ml/min per 1.73 m 2 . Cox proportional hazards models assessed the association between the baseline hyperfiltration status and the subsequent risk of reaching an eGFR 2 . Results Of the 446 participants, 106 (24%) had hyperfiltration (iGFR levels ≥140 ml/min per 1.73 m 2 ) at baseline. Over a median follow-up of 28 (interquartile range, 23, 33) years, 53 developed an eGFR 2 . The cumulative incidence of eGFR 2 at 28 years of follow-up was 11.0% among participants with hyperfiltration at baseline, compared with 12.8% among participants with baseline GFR 2 . Hyperfiltration was not significantly associated with subsequent risk of developing an eGFR 2 in an unadjusted Cox proportional hazards model (hazard ratio, 0.83; 95% confidence interval, 0.43 to 1.62) nor in an adjusted model (hazard ratio, 0.77; 95% confidence interval, 0.38 to 1.54). Application of alternate thresholds to define hyperfiltration (130 or 150 ml/min per 1.73 m 2 ) showed similar findings. Conclusions Early hyperfiltration in patients with type 1 diabetes was not associated with a higher long-term risk of decreased GFR. Although glomerular hypertension may be a mechanism of kidney injury in DKD, higher total GFR does not appear to be a risk factor for advanced DKD.

OBJECTIVE High-sensitivity cardiac troponin-T (hs-cTnT) and N-terminal prohormone of B-type natriuretic peptide (NT-proBNP), biomarkers of cardiovascular disease (CVD) and heart failure, respectively, have not been widely studied in type 1 diabetes (T1D). We evaluated whether their assessment in T1D enhances the prediction of CVD and major adverse cardiovascular events (MACE). RESEARCH DESIGN AND METHODS hs-cTnT and NT-proBNP were analyzed on the Roche Cobas E601 using the first available stored specimen (n = 581; mean age 29 years and diabetes duration 21 years). CVD was defined as CVD death, myocardial infarction, coronary revascularization, angina, ischemia, or stroke, and MACE as CVD death, myocardial infarction, or stroke. RESULTS Median hs-cTnT (5.0 ng/L; interquartile range CONCLUSIONS Sex differences were observed in the concentration and predictive ability of hs-cTnT and NT-proBNP in T1D. Overall, their addition to traditional risk factor models increased the area under the curve for neither CVD nor MACE.

Background Many CpGs become hyper or hypo-methylated with age. Multiple methods have been developed by Horvath et al. to estimate DNA methylation (DNAm) age including Pan-tissue, Skin & Blood, PhenoAge, and GrimAge. Pan-tissue and Skin & Blood try to estimate chronological age in the normal population whereas PhenoAge and GrimAge use surrogate markers associated with mortality to estimate biological age and its departure from chronological age. Here, we applied Horvath’s four methods to calculate and compare DNAm age in 499 subjects with type 1 diabetes (T1D) from the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications (DCCT/EDIC) study using DNAm data measured by Illumina EPIC array in the whole blood. Association of the four DNAm ages with development of diabetic complications including cardiovascular diseases (CVD), nephropathy, retinopathy, and neuropathy, and their risk factors were investigated. Results Pan-tissue and GrimAge were higher whereas Skin & Blood and PhenoAge were lower than chronological age (p < 0.0001). DNAm age was not associated with the risk of CVD or retinopathy over 18–20 years after DNAm measurement. However, higher PhenoAge (β = 0.023, p = 0.007) and GrimAge (β = 0.029, p = 0.002) were associated with higher albumin excretion rate (AER), an indicator of diabetic renal disease, measured over time. GrimAge was also associated with development of both diabetic peripheral neuropathy (OR = 1.07, p = 9.24E−3) and cardiovascular autonomic neuropathy (OR = 1.06, p = 0.011). Both HbA1c (β = 0.38, p = 0.026) and T1D duration (β = 0.01, p = 0.043) were associated with higher PhenoAge. Employment (β = − 1.99, p = 0.045) and leisure time (β = − 0.81, p = 0.022) physical activity were associated with lower Pan-tissue and Skin & Blood, respectively. BMI (β = 0.09, p = 0.048) and current smoking (β = 7.13, p = 9.03E−50) were positively associated with Skin & Blood and GrimAge, respectively. Blood pressure, lipid levels, pulse rate, and alcohol consumption were not associated with DNAm age regardless of the method used. Conclusions Various methods of measuring DNAm age are sub-optimal in detecting people at higher risk of developing diabetic complications although some work better than the others.

BackgroundEvaluating associations of circulating electrolytes with atrial fibrillation (AF) and burden of supraventricular arrhythmias can give insights into arrhythmia pathogenesis.MethodsWe conducted a cross-sectional analysis of 6,398 participants of the Atherosclerosis Risk in Communities (ARIC) study, ages 71-90, with data on serum electrolytes (magnesium, calcium, potassium, phosphorus, chloride, sodium). Prevalence of AF was determined from study 12-lead electrocardiograms and prior history of AF-related hospitalizations. A subset of 317 participants also underwent electrocardiographic recordings for up to 14 days using the Zio®patch. Burden of other supraventricular arrhythmias [premature atrial contractions (PACs), supraventricular tachycardia] was determined with the Zio®patch. We used multivariable logistic and linear regression adjusting for potential confounders to determine associations of electrolytes with arrhythmia prevalence and burden.ResultsAmong 6,394 eligible participants, 614 (10%) had prevalent AF. Participants in the top quintiles of magnesium [odds ratio (OR) 0.82, 95% confidence interval (CI) 0.62, 1.08], potassium (OR 0.82, 95%CI 0.68, 1.00), and phosphorus (OR 0.73, 95%CI 0.59, 0.89) had lower prevalence of AF compared to those in the bottom quintiles. No clear association was found for circulating chloride, calcium or sodium. Higher concentrations of circulating calcium were associated with lower prevalence of PACs using a standard 12-lead electrocardiogram, while higher concentrations of potassium, chloride and sodium were associated with higher PAC prevalence. Circulating electrolytes were not significantly associated with the burden of PACs or supraventricular tachycardia among a subset of 317 participants with extended electrocardiographic monitoring.ConclusionConcentrations of circulating electrolytes present complex associations with selected supraventricular arrhythmias. Future studies should evaluate underlying mechanisms.

High-sensitivity troponin T (hsTnT), a marker of CVD, and N-Terminal pro B-Type Natriuretic Peptide (NT-proBNP), a marker of heart failure, have not been widely studied in type 1 diabetes. We thus assessed the ability of these markers to independently predict CVD and MACE in a cohort with childhood-onset T1D (n=583, mean age 29 and duration 21 years) during a median follow-up of 21 years. CVD was defined as CVD death, myocardial infarction, revascularization, angina, or ischemia, and MACE as CVD death, myocardial infarction, or stroke. hsTnT and NT-proBNP were assessed with electrochemiluminescence immunoassays. Median hsTnT was 5.0 ng/L (IQR: 2.0, 10.0) and median NT-proBNP was 22.0 pg/mL (7.0, 61.0). In Cox proportional hazards models allowing for diabetes duration, gender, BMI, smoking status, HbA1c, hypertension status, HDL and non-HDL cholesterol, white blood cell count, estimated glomerular filtration rate and albumin excretion rate, both log hsTnT (HR=1.30, 95% CI: 1.06-1.59) and log NT-proBNP (HR=1.29, 95% CI: 1.13-1.48) independently predicted CVD. However, the prediction of CVD between models with and without these two markers improved only marginally (Uno’s concordance statistic p=0.06). Furthermore, log hsTnT was a slightly weaker predictor of MACE (HR=1.22, 95% CI: 0.97-1.55) compared with log NT-proBNP (HR=1.28, 95% CI: 1.11-1.47). The addition of these two markers to models already including traditional risk factors did not enhance MACE prediction (p=0.39). In conclusion, although hsTnT and NT-proBNP independently predicted both CVD and MACE, they marginally increased the area under the curve only for CAD in this type 1 diabetes cohort. Disclosure T. Costacou: None. A.K. Saenger: None. T.J. Orchard: Consultant; Self; Boehringer Ingelheim International GmbH. Funding National Institutes of Health (DK34818); Rossi Memorial Fund

The IFCC Committee on Clinical Applications of Cardiac Bio-Markers (C-CB) has directives and initiatives focused on providing evidence-based educational resources to aid and improve understanding around key analytical and clinical aspects of cardiac biomarkers used in clinical practice and the research setting. As a task force, we have previously published position statements and recommendations focused on use and analytical aspects of high-sensitivity cardiac troponin assays. The current educational document is the first from the C-CB highlighting important biochemical, analytical, and clinical aspects as they relate to the natriuretic peptides (NPs), including B-type natriuretic peptide (BNP) and N-terminal pro–B-type natriuretic peptide (NT-proBNP), with a focus on heart failure.

INTRODUCTION Glomerular hyperfiltration has long been considered to be a major contributing factor to the development of diabetic kidney disease but most studies assessed increased albumin excretion rather than reduced GFR as an outcome. To address whether early glomerular hyperfiltration results in subsequent increased risk of clinically significant loss of GFR, namely Stage 3 CKD (eGFR

Systemic mastocytosis (SM) is a disorder characterized by the excessive accumulation of clonally derived mast cells in various tissues. When triggered, mast cells release large amounts of histamine, prostaglandins and leukotrienes. Leukotriene E4 (LTE4) is the primary stable metabolite of total cysteinyl leukotrienes. We hypothesized that secretion of LTE4 would be increased in SM and could be used alone or in combination with current urinary biomarkers to optimize screening for SM.LTE4 was measured by liquid chromatography followed by tandem mass spectrometry (LC-MS/MS). Analytical assay validation was performed using residual urine specimens. LTE4 results were normalized to urine creatinine for clinical use. Reference interval was established using a healthy volunteer cohort. Clinical sensitivity and specificity for SM detection were determined by measuring urinary biomarkers (LTE4, N-methyl histamine [NMH] and 11β-prostaglandin F2α [BPG]) in a cohort of 409 patients referred to allergy specialists, 66 (16%) of which were diagnosed with SM.Urinary LTE4 measurement was accurate, precise and linear across a range of 31-3020pg/mL. The 95th percentile of the reference interval population was104pg/mg creatinine. Median urine LTE4 concentrations were significantly higher among patients with SM (97pg/mg cr. vs. 50pg/mg cr.; p0.01). Elevated urinary LTE4 was 48% sensitive and 84% specific for SM. Clinical sensitivity was 53% for BPG (1000ng/mL) and 71% for NMH (200ng/mL). Incorporating all three urinary metabolites improved the SM diagnostic sensitivity to 97%, with minimal change in specificity.We have developed a sensitive and precise LC-MS/MS assay for quantitation of LTE4 in urine. Incorporating LTE4 into a panel including BPG and NMH provides a much-needed screening tool for a complicated disease with non-specific symptoms and invasive confirmatory testing.

Background B-Type natriuretic peptides (BNP) and cardiac troponin T (cTnT) predict cardiovascular events in heart failure (HF) patients, but additional refinement in risk stratification may be possible by targeting pathways leading to fibrosis. We aimed to assess the value of serial measurements of soluble suppression of tumorigenicity 2 (sST2) and galectin-3 to identify risk for adverse pathophysiologic processes. Methods New York Heart Association (NYHA) functional class III–IV HF patients (n = 180; LVEF ≤40%) were prospectively evaluated with biomarkers collected every 3 months over 2 years and analyzed regarding a primary end point of death/cardiac transplantation and a secondary end point of HF-related hospitalization or death/transplantation. Results Time-dependent univariate analyses demonstrated that elevations of sST2 (≥49.3 ng/mL male, ≥33.5 ng/mL female) and galectin-3 (≥22.1 ng/mL) were predictive of the primary and secondary end points. In multivariate models adjusted for BNP, cTnT, and clinical variables, sST2 but not galectin-3 remained an independent predictor (hazard ratio 3.22, 95% confidence interval 1.76–5.89; P Conclusions Serial monitoring of sST2 (indicating myocardial fibrosis and remodeling) and cTnT (reflecting myocardial injury) identifies highest-risk HF outpatients and may be valuable to guide patient tailored therapy during follow-up evaluations. Serial galectin-3 monitoring in ambulatory HF patients may not be of benefit.

Two interferences recently brought to the forefront as patient safety issues include hemolysis (hemoglobin) and biotin (vitamin B7). The International Federation for Clinical Chemistry Committee on Cardiac Biomarkers (IFCC-CB) obtained input from a majority of cTn and NP assay manufacturers to collate information related to high-sensitivity (hs)-cTnI, hs-cTnT, contemporary, and POC cTn assays, and NP assays interferences due to hemolysis and biotin. The information contained in these tables was designed as educational tools to aid laboratory professionals and clinicians in troubleshooting cardiac biomarker analytical results that are discordant with the clinical situation. Keywords: biotin; hemolysis; interferences; natriuretic peptide; troponin Cardiac troponin I and T (cTnI, cTnT) and the natriuretic peptides (NP; B-type natriuretic peptide, BNP; N Terminal-proBNP; NT-proBNP) are the primary cardiac biomarkers utilized in the diagnosis of myocardial injury and infarction (MI) and heart failure (HF), respectively. As with any clinical laboratory test, there are exogenous and endogenous factors that adversely interfere with the analytical performance of the cTn and NP assays, potentially resulting in inappropriate clinical interpretation of the results if the interferences are not identified. Analytical interferences are particularly concerning when dealing with cardiac biomarker assays, which are utilized to make time sensitive critical clinical decisions. Two interferences recently brought to the forefront as patient safety issues include hemolysis (hemoglobin) and biotin (vitamin B7, vitamin H, coenzyme R). The International Federation for Clinical Chemistry Committee on Cardiac Biomarkers (IFCC-CB) obtained input from a majority of cTn and NP assay manufacturers to collate information related to high-sensitivity (hs)-cTnI, hs-cTnT, contemporary, and POC cTn assays (Table 1) [1], and NP assays (Table 2) [2] interferences due to hemolysis and biotin. The information contained in these tables was designed as educational tools to aid laboratory professionals and clinicians in troubleshooting cardiac biomarker analytical results that are discordant with the clinical situation.

Cardiac troponin (cTn) testing has evolved significantly in recent times. Because of increased sensitivity, its use has shifted from a marker used to help diagnose acute myocardial infarction (MI) to a marker than can be used in the outpatient setting, as well as for both detection of myocardial injury and risk-stratification. Its main role remains in the diagnosis of acute MI and the risk-stratification of patients presenting with suspected acute coronary syndrome. The analytical improvements in assays leading to precise high-sensitivity cTn assays have contributed to the development of numerous strategies to identify patients at both low- and high-risk for acute MI within a few hours. These approaches should reduce overcrowding in the emergency room and expedite triaging. The ability of measuring cTn in most patients using high-sensitivity (hs) assays has allowed for the opportunity to examine its use in the detection of cardiotoxicity in patients undergoing chemotherapy, as well as exploring the application in both primary and secondary prevention of coronary artery disease. This particular field of research has become increasingly complex, partly due to the numerous cTn assays available (I and T; point-of-care, contemporary, hs) and an array of approaches in which one can use the test. The purpose of this document is to summarize the analytical and clinical information relevant to cTn assays, in particular, hs-cTn assays, and describe present and future opportunities for use of cTn in acute cardiac care and in the outpatient setting.

We investigated residual beta cell function in participants from the DCCT/EDIC study with an average of 35 (range 27, 48) years duration of T1D. Between 2015-2017 after 22-24 years of follow-up in EDIC, a 4-hour mixed meal tolerance test was administered to 944 participants and 7 timed plasma specimens were collected and assayed for C-peptide using a chemiluminescent immunoassay (Roche). We defined a significant post-stimulus response as a peak C-peptide concentration >0.03 nmol/L, based on an earlier DCCT study which demonstrated that the risk of microvascular disease progression was markedly higher among participants who entered the trial with values below this concentration. Overall, 71 (7.5%) participants were classified as “responders” with a median peak C-peptide of 0.10 nmol/L (IQR 0.06, 0.15). Among the 873 participants classified as “non-responders”, 46 had detectable peak C-peptide between 0.003 (limit of detection) and 0.029 nmol/L. Responders were slightly older than non-responders (58.5 ± 6.2 vs. 56.5 ± 6.8 y; p=0.02), yet had similar age of onset of diabetes (22.5 ± 7.0 vs. 21.4 ± 7.8 y) and duration of diabetes (35.9 ± 5.1 vs. 35.0 ± 4.9 y). Compared to non-responders, responders had lower HbA1c values (8.6 ± 1.7 vs. 8.9 ± 1.5%; p=0.01) and higher stimulated C-peptide (0.22 ± 0.14 vs. 0.11 ± 0.11 nmol/L; p In conclusion, beta cell function persists in some very long duration T1D patients and is associated with clinically meaningful reductions in the frequency of severe hypoglycemia. Disclosure R. Gubitosi-Klug: None. B. Braffett: None. S.M. Hitt: None. V. Arends: None. M. Steffes: None. A.K. Saenger: Advisory Panel; Self; Alere Inc. J. Lachin: Board Member; Self; AbbVie Inc., Celgene Corporation. J.P. Palmer: None.

The use of soluble cardiac biomarkers such as N-terminal pro-brain natriuretic peptide (NT-proBNP) and troponin has revolutionized prognostication for patients with AL amyloidosis. Soluble ST2 (sST2) and galectin-3 have also been reported to have prognostic value in other cardiac patient populations. We identified 502 patients with AL amyloidosis, who provided a research sample and consent to review their medical records between 1/1/2006-12/31/2010 within 90 days of their diagnosis. Samples were assayed for sST2 and galectin-3. Within this AL amyloidosis population, overall survival (OS) was 25.5 months (95% CI 18, 35.7 months). Receiver operating curve analyses were done to detect the best cut-points for sST2 and galectin-3 to predict both 1- and 5-year OS. The respective cut points for sST2 were 30 and 29.7 ng/mL, while the median sST2 for the entire population was 31 ng/mL (IQR 19.8, 53.6). The respective cut points for galectin-3 were 11 and 10.4 ng/mL while the median for the entire population was 16.6 ng/mL (IQR 11.5, 24.0). Although on univariate analysis, both sST2 and galectin-3 were prognostic, upon multivariate analysis, only sST2 was independent of troponin, NT-proBNP, serum immunoglobulin free light chain, and blood pressure. Not only did sST2 add to previously reported prognostication systems, but a novel prognostication 5-point system including sST2 was possible. The addition of sST2 - but not galectin-3 - to existing prognostication systems for patients with AL amyloidosis strengthens the ability to predict for death.

OBJECTIVE Women with type 1 diabetes have increased risk of infertility compared to women without diabetes even after adjustment for irregular menses, but aetiologies are incompletely understood. Our aim was to examine the prevalence of abnormalities in ovarian markers consistent with polycystic ovary syndrome in women with type 1 diabetes and associations with irregular menses and diabetes-specific variables. DESIGN, PATIENTS AND MEASUREMENTS We conducted a secondary analysis of women in the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications Study (DCCT/EDIC), a randomized trial and observational follow-up of intensive insulin therapy for type 1 diabetes. We included women with anti-Mullerian hormone (AMH) measurements among women not using oral contraceptives (n = 187). Initial AMH and testosterone measures were performed between EDIC years 1 and 4. History of irregular menses was assessed annually. RESULTS The median age of women was 35 (interquartile ratio 29, 40) years; 133 (35%) had elevated AMH and 62 (17%) reported irregular menses. Twelve per cent of women had relative elevations in total testosterone. In multivariable models, lower insulin dosages were associated with higher AMH concentrations (P = .0027), but not diabetes duration, glycemic control, body mass index or irregular menses. Neither irregular menses nor diabetes-specific variables were associated with testosterone concentrations. CONCLUSIONS Among women with type 1 diabetes in their thirties, abnormalities in ovarian markers are common and not associated with irregular menses and thus may partially account for decreased fecundity in women with type 1 diabetes.

Objective: Familial hypercholesterolemia (FH) can be due to mutations in LDLR, PCSK9, and APOB. In phenotypically defined patients, a subset remains unresponsive to lipid-lowering therapies and requires low density-lipoprotein (LDL) apheresis treatment. In this pilot study, we examined the genotype/phenotype relationship in patients with dyslipidemia undergoing routine LDL apheresis. Design: LDLR, APOB, and PCKS9 were analyzed for disease-causing mutations in seven patients undergoing routine LDL apheresis. Plasma and serum specimens were collected pre- and post-apheresis and analyzed for lipid concentrations, Lp(a) cholesterol, and lipoprotein particle concentrations (via NMR). Results: We found that four patients harbored LDLR mutations and of these, three presented with xanthomas. While similar reductions in LDL-cholesterol (LDL-C), apolipoprotein B, and LDL particles (LDL-P) were observed following apheresis in all patients, lipid profile analysis revealed the LDLR mutation-positive cohort had a more pro-atherogenic profile (higher LDL-C, apolipoprotein B, LDL-P, and small LDL-P) pre-apheresis. Conclusion: Our data show that not all clinically diagnosed FH patients who require routine apheresis have genetically defined disease. In our small cohort, those with LDLR mutations had a more proatherogenic phenotype than those without identifiable mutations. This pilot cohort suggests that patients receiving the maximum lipid lowering therapy could be further stratified, based on genetic make-up, to optimize treatment. J. Clin. Apheresis 29:256–265, 2014. © 2014 Wiley Periodicals, Inc.

Altered concentrations of bile acid (BA) in the colon can cause diarrhea or constipation. More than 25% of patients with irritable bowel syndrome with diarrhea or chronic diarrhea in Western countries have BA malabsorption (BAM). As BAM is increasingly recognized, proper diagnostic methods are needed to help direct the most effective course of treatment for the chronic bowel dysfunction. We review the methodologies, advantages, and disadvantages of tools that directly measure BAM: the 14 C-glycocholate breath and stool test, the 75 selenium homotaurocholic acid test (SeHCAT), and measurements of 7 α-hydroxy-4-cholesten-3-one (C4) and fecal BAs. The 14 C-glycocholate test is laborious and no longer widely used. The 75 SeHCAT has been validated but is not available in the United States. Measurement of serum C4 is a simple and accurate method that can be used for most patients but requires further clinical validation. Assays to quantify fecal BA (total and individual levels) are technically cumbersome and not widely available. Regrettably, none of these tests are routinely available in the United States; assessment of the therapeutic effects of a BA binder is used as a surrogate for diagnosis of BAM. Recent data indicate the advantages to studying fecal excretion of individual BAs and their role in BAM; these could support the use of the fecal BA assay, compared with other tests. Measurement of fecal BA levels could become a routine addition to the measurement of fecal fat in patients with unexplained diarrhea. Availability ultimately determines whether the C4, SeHCAT, or fecal BA test is used; more widespread availability of such tests would enhance clinical management of these patients.

Acute coronary syndrome (ACS) encompasses a pathophysiological spectrum of cardiovascular diseases, all of which have significant morbidity and mortality. ACS was once considered an acute condition; however, new treatment strategies and improvements in biomarker assays have led to ACS being an acute and chronic disease. Cardiac troponin is the preferred biomarker for the diagnosis of myocardial infarction, and there is considerable interest and efforts toward development and implementation of high-sensitivity cardiac troponin (hs-cTn) assays worldwide. Analytical and clinical performance characteristics of hs-cTn assays as well as testing limitations are important for laboratorians and clinicians to understand in order to utilize testing appropriately. Furthermore, expanding the clinical utility of hs-cTn into other cohorts such as asymptomatic community dwelling populations, heart failure, and chronic kidney disease populations supports novel opportunities for improved short- and long-term prognosis.

BACKGROUND Aspirin's therapeutic action is via inhibition of platelet cyclooxygenase 1 (COX-1) thromboxane A2 (TxA2) production. The aim of this study was to evaluate TxA2 production, in the absence of platelet COX-1 activity, in coronary atherosclerotic heart disease patients with and without atherothrombotic myocardial infarction (MI). METHODS AND RESULTS TxA2 production, in the absence of platelet COX-1 activity, was evaluated in 44 patients taking aspirin on 3 commercially available assays that detect metabolites of TxA2 in the urine. Two assays measure urine 11-dehydro-thromboxane B2 (TxB2) alone and 1 measures urine 11-dehydro-TxB2 plus 11-dehydro-2,3-dinor-TxB2. Platelet COX-1 inhibition was confirmed on

Cardiac troponin [cardiac troponin I (cTnI) and cTnT] has become globally recognized as the standard biomarker for the diagnosis of acute myocardial infarction (AMI).8 With improvements in the analytical characteristics of cardiac troponin assays, particularly imprecision at low measurable concentrations, high-sensitivity cardiac troponin (hs-cTn) assays are now being implemented worldwide; but not in the US since the Food and Drug Administration has not yet cleared them for clinical use. With the implementation of hs-cTn assays, improvements in clinical care are beginning to be observed in the peer-reviewed literature. These improvements include early rule out (early hospital discharge) and rule in (right bed for appropriate patient) for MI and improved risk stratification for patients presenting with symptoms suggestive of ischemia, with improved short- and long-term outcomes. Further hs-cTn assays have been part of solidifying the definition of myocardial injury, based on an increased cardiac troponin concentration above the 99th percentile upper reference limit. The high-sensitivity assays have improved the clinical understanding that not all cardiac troponin increases are MI and that patients with nonischemic disease also have increases in cardiac troponin that must be managed accordingly. This Q&A provides the opportunity for 3 cardiologists, 2 laboratory medicine scientists, and 1 emergency medicine physician to share their experiences with the evolving role of cardiac troponin testing in their practices. Ideally, the messages they share will assist in better harmonizing the appropriate utilization of high-sensitivity assays worldwide as we transition away from contemporary cardiac troponin assays. Should all medical centers have a uniform serial order set to assist in ruling in/out AMI? Should a single cardiac troponin order be available? What would your ideal serial order set (timing) be? Allan S. Jaffe: Medical centers would benefit from developing consistent, uniform serial orders to rule in/out AMI. These serial orders should be agreed …

High-sensitivity cardiac troponin assays are being introduced clinically for earlier diagnosis of acute myocardial infarction (AMI). We evaluated the analytical performance of a high-sensitivity cardiac troponin T assay (hscTnT, Roche Diagnostics) in a multicenter, international trial.Three US and 5 European sites evaluated hscTnT on the Modular® Analytics E170, cobas® 6000, Elecsys 2010, and cobas® e 411. Precision, accuracy, reportable range, an inter-laboratory comparison trial, and the 99th percentile of a reference population were assessed.Total imprecision (CVs) were 4.6-36.8% between 3.4 and 10.3 ng/L hscTnT. Assay linearity was up to 10,000 ng/L and the limit of blank and detection were 3 and 5 ng/L, respectively. The 99th percentile reference limit was 14.2 ng/L (n=533). No significant differences between specimen types, assay incubation time, or reagent lots existed. A substantial positive bias (76%) exists between the 4th generation and hscTnT assays at the low end of the measuring range (50 ng/L). hscTnT serum pool concentrations were within 2SD limits of the mean of means in the comparison trial, indicating comparable results across multiple platforms and laboratories.The Roche hscTnT assay conforms to guideline precision requirements and will likely identify additional patients with myocardial injury suspicious for AMI.

1. Amy K. Saenger, PhD, DABCC[⇑][1] 1. Laboratory Medicine and Pathology Mayo Clinic 200 First Street SW Rochester, MN 55905 1. Address for Correspondence: Amy K. Saenger, PhD, DABCC , Director, Central Clinical Laboratory/Central Processing, Assistant Professor, Laboratory Medicine and Pathology Mayo Clinic 200 First Street SW Rochester, MN 55905 507-266-6494 saenger.amy{at}mayo.edu In its Fall, 2009 issue, Clinical Laboratory Science featured a Focus Series on Cardiovascular Risk Assessment. This series contained articles on B-type natriuretic peptide and genetic markers of cardiovascular disease and explored the links between decreased serum vitamin-D levels and cardiovascular disease. Traditionally, cardiovascular risk assessment has referred to markers that help predict long-term mortality and morbidity for heart disease. Markers like LDL, HDL, triglycerides, total cholesterol, hsCRP, BNP and many others make up this group. Acutely however, in cases of suspected myocardial infarction, cardiovascular assessment relies on a very different class of serum markers. Measurement of CK-MB and troponin proteins allows us to confirm or rule out damage to the myocardium. These markers are in obvious contrast to risk markers that are used as tools to assess a person's future risk for cardiovascular events. When considering markers for myocardial infarct, laboratorians know that CK-MB and troponin are both used to give diagnostic and sometimes even prognostic information. In this article, which is an extension of the Fall 2009 Focus series, we review the progress of these two myocardial markers while contemplating the question, ‘is it time to phase-out CK-MB testing given the advances and advantages of troponin testing?’ Modern diagnosis of myocardial infarction includes the use of blood biomarkers, which can also be used for risk assessment and for guiding interventional and non-interventional therapies. An ideal marker of cardiac necrosis should exhibit the following characteristics: cardiac specificity, tissue sensitivity, early and stable release after necrosis, predictable clearance, and the… [1]: #corresp-1

Background: Stroke is a devastating condition encompassing a wide range of pathophysiological entities that include thrombosis, hemorrhage, and embolism. Current diagnosis of stroke relies on physician clinical examination and is further supplemented with various neuroimaging techniques. A single set or multiple sets of blood biomarkers that could be used in an acute setting to diagnosis stroke, differentiate between stroke types, or even predict an initial/reoccurring stroke would be extremely valuable.Content: We discuss the current classification, diagnosis, and treatment of stroke, focusing on use of novel biomarkers (either solitary markers or multiple markers within a panel) that have been studied in a variety of clinical settings.Summary: The current diagnosis of stroke remains hampered and delayed due to lack of a suitable mechanism for rapid (ideally point-of-care), accurate, and analytically sensitive biomarker-based testing. There is a clear need for further development and translational research in this area. Potential biomarkers identified need to be transitioned quickly into clinical validation testing for further evaluation in an acute stroke setting; to do so would impact and improve patient outcomes and quality of life.

A 43-year-old African-American man with a history of hypertension, depression, and chronic alcohol abuse presented to the emergency service of an outside hospital complaining of chest pain. Laboratory testing indicated hepatocellular injury with aspartate aminotransferase (AST)1 of 14000 U/L (reference interval 5–41 U/L) and alanine aminotransferase (ALT) of 6400 U/L (reference interval 8–45 U/L). Because laboratory indicators of liver function worsened, the patient was reinterviewed and confessed to having attempted suicide 3 days prior by ingesting about one-half gallon (approximately 4 L) of vodka and one-half bottle of extra-strength acetaminophen. The patient was administered a bolus of N-acetylcysteine (NAC) at the outside hospital and referred to our institution because of concern for progression to fulminant hepatic failure. Laboratory tests were repeated and results were consistent with significant hepatocellular damage secondary to acetaminophen poisoning, including increased AST of 11 000 U/L (reference interval 8–48 U/L), ALT of 6510 U/L (reference interval 7–55 U/L), total bilirubin of 395 μmol/L (23.1 mg/dL) [reference interval 2–17 μmol/L (0.1–1.0 mg/dL)], and direct-bilirubin of 207 μmol/L (12.1 mg/dL) [reference interval

The Universal Definition of Myocardial Infarction globally endorses cardiac troponin (T and I; cTnT, cTnI) as the biomarker of choice for the diagnosis and assessment of acute coronary syndrome (ACS) and should be utilized routinely in patients with symptoms suggestive of acute myocardial infarction (AMI) [1]. Despite the widespread use of troponin in clinical practice there remain a number of pre-analytical, analytical and interpretive issues which can confound clinical interpretation and will likely be magnified with high-sensitivity troponin assays. The following case studies and discussion highlight some of these issues and nuances associated with troponin assays.

BACKGROUND We assessed the impact of clinical decision support (CDS) rules within the electronic health record for ionized calcium (iCa), serum magnesium (Mg), and N-terminal pro-B-type natriuretic peptide (NT-proBNP) in intensive care unit (ICU) inpatients at a large academic center. METHODS A repeat order for measurement of iCa or Mg placed within 24 (iCa) or 48 (Mg) h of a previously nonactionable result, or additional orders for NT-proBNP beyond 1 within a single hospitalization, triggered a CDS pop-up alert showing the prior result and offering the opportunity to cancel the order or to place the order after entering an indication for repeat testing. The number of tests performed for each of these analytes and incidence of adverse clinical outcomes potentially associated with hypocalcemia or hypomagnesemia were compared between the 90-day period before CDS implementation and two 90-day periods immediately following. RESULTS iCa test volumes decreased by 48%, Mg by 39%, and NT-proBNP by 28% in the 90-day period immediately following implementation and remained decreased by 54%, 49%, and 22%, respectively, during the following 90-day period (all P values 0.17). CONCLUSIONS Implementation of CDS dramatically decreased repeat testing of iCa, Mg, and NT-proBNP without adversely impacting clinical outcomes in the ICU. Expansion of the rules from the ICU units to include the entire hospitalized patient population and expansion to additional analytes is expected to lead to further reductions in testing.

Objectives Soluble ST2 (ST2) and galectin-3 (Gal3) are biomarkers of myocardial fibrosis and remodeling. This study provides a foundation for the use of ST2 and Gal3 in pediatric patients by assessing values of these biomarkers among children without heart failure. Design and methods Sera from 240 children, 40 males and 40 females from each of three age groups, (2–6 years, 7–11 years, and 12–17 years) without heart failure were identified from residual clinical testing. Serum ST2 and Gal3 were measured by ELISA. Results Serum ST2 increased with age among males, but not females. However, the difference was not statistically significant at the 95th or 97.5th percentiles. No relationship was found between serum Gal3 concentrations and age or gender. Central 95th percentiles (2.5th to 97.5th) were 9–50 ng/mL for ST2 and 7–33 ng/mL for Gal3. Conclusions We have presented baseline, normative data for ST2 and Gal3 in children. This will allow for study of the utility of these biomarkers in children with heart disease.

Serum levels of 25-hydroxyvitamin D are important in establishing true vitamin D levels in humans. The purposes of this study were to develop a sensitive, specific liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for detection of 25-hydroxyvitamin D(2) and D(3) and establish reference intervals for these analytes. Chromatographic separation of 25(OH)D(2) and 25(OH)D(3) was achieved after adding deuterated Delta(9)-tetrahydrocannabinol (D(9)-THC-D(3)) and organic extraction. The 3 ions were ionized using positive electrospray ionization and detected in the multiple-reaction monitoring mode using mass (m)/charge (z) transitions of 318.15 > 196.20 (Delta(9)-THC-D(3)), 401.15 > 365.2 (25(OH)D(3)), and 413.15 > 355.20 (25(OH)D(2)). Reference interval study results were compared with current 25(OH)D recommendations. Elution of 25(OH)D(2), 25(OH)D(3), and Delta(9)-THC-D(3) was achieved after 3.0 minutes (total run time, 6.0 minutes). Within- and between-run coefficients of variation were less than 11%. Deming regression of radioimmunoassay and LC-MS/MS methods for total 25(OH)D levels yielded a slope of 0.97 (95% confidence interval, 0.88-1.05) and y-intercept of -1.74 ng/mL. Reference intervals were less than recommended levels (D(2), 0.0-12.1; D(3), 5.5-41.4; total vitamin D, 6.0-43.5 ng/mL [0-30, 14-103, 15-109 nmol/L, respectively]) with no statistically significant differences in race, age, or sex. This LC-MS/MS method provides a rapid, accurate, sensitive, and cost-effective alternative to other methods for detection of 25(OH)D(2) and 25(OH)D(3) at nanomolar concentrations.

Smith-Lemli-Opitz syndrome (SLOS) is a recessive disorder characterized by multiple anomalies (cleft palate, postaxial polydactyly, 2/3 toe syndactyly, hypospadias, and cardiac defects), microcephaly, growth restriction, and intellectual disability. SLOS is caused by mutations in the DHCR7 gene, which encodes 7-dehydrocholesterol reductase. Decreased enzyme activity results in low levels of plasma cholesterol and elevated cholesterol precursors, including 7-dehydrocholesterol (7DHC), which is diagnostic of SLOS. The molecular mutation detection rate is as high as 96% (1). Here, we describe pregnancy in an individual with SLOS for the first time. Our patient is a 36-year-old referred to genetics during her second pregnancy for recurrence risk of her minor congenital anomalies. The patient's first pregnancy was achieved with clomiphene ovulation induction and intrauterine insemination with donor sperm, and resulted in a spontaneous abortion at approximately four to five weeks gestation. Her second pregnancy was achieved spontaneously. The patient has a history of a submucosal cleft palate and “fused baby teeth.” Physical examination revealed a small mouth and high-pitched voice. The hands were small but without any digital anomalies. The feet were also small, and there was almost complete cutaneous syndactyly between the second and third toes bilaterally (Figure 1). The patient had short stature (height 147.7 cm, less than third percentile). Her weight was 73.0 kg, head circumference was 51.5 cm, BSA was 1.8 m2, and BMI was 33.5 kg/m2. She had normal intellect, with no reported history of learning disabilities, developmental delays, or behavioral abnormalities. She completed high school and college education without need for special education or tutoring. Figure 1 Patient's feet. Note bilateral 2/3 toe syndactyly. SLOS was suspected given the patient's congenital anomalies. 7DHC plasma levels were elevated on several occasions, including postpartum time points (Table I). The patient was not treated with any drugs that cause elevated 7DHC (e.g. Aripiprazole). Molecular testing of DHCR7 revealed the common c.964-1G>C mutation, and a novel missense variant, c.1083C>G (p.Phe361Leu), not reported in dbSNP. The phenylalanine residue is conserved across species. The patient's father was unavailable for testing, but the patient's mother tested positive for the c.964-1G>C mutation and negative for the c.1083C>G variant, strongly suggesting that the two DHCR7 alterations are in trans and therefore likely causative of the patient's phenotype. Table 1 Results of biochemical testing performed during and after the patient's pregnancy. We measured sterols in fibroblasts grown under cholesterol replete (FBS) and cholesterol deficient (LPDS) conditions (performed at NIH, Bethesda, MD) (2). When patient skin fibroblasts were cultured in cholesterol depleted medium, the mean fraction of 7DHC to total sterols was 1.8%. These values are consistent with the mildest identified patients we have identified to date. Cholesterol levels are typically elevated during pregnancy (3); however, this is not expected in SLOS. Due to the patient's personal and family history of hypercholesterolemia, APOB and LDLR gene analysis were conducted. The patient tested negative for the common R3500W and R3500Q APOB mutations. LDLR gene sequencing revealed two copies of the c.1773C>T polymorphism. This polymorphism results in decreased splicing efficiency of exon 12, leading to increased total and LDL-cholesterol (4). We postulate that this polymorphism has a protective effect by counteracting the SLOS-associated cholesterol synthesis defect, explaining the patient's mild phenotype. Guidelines for management of SLOS during pregnancy do not exist due to the lack of reported cases. The diagnosis of SLOS in our patient resulted in modifications of her medical care. Changes in management included serial monitoring of cholesterol and 7DHC levels with dietary intervention to increase exogenous cholesterol and decrease the accumulation of potentially toxic cholesterol precursors. The patient met with a dietician for specific dietary management recommendations. A cholesterol loading diet, including lean meats, cheese, and eggs, was recommended beginning at approximately 29 weeks gestation. Serial fetal ultrasounds were performed due to concern for intrauterine growth restriction, heart defects, or other anomalies associated with either SLOS or toxicity due to cholesterol precursors crossing the placenta. An obstetrical anesthesia consult was also ordered due to obesity and history of cleft palate. We followed this patient throughout her pregnancy. She underwent cesarean section at term due to breech presentation with delivery of a non-dysmorphic, healthy female. Short fallopian tubes were incidentally noted (6.5 cm versus 9.0-11.0 cm average). SLOS is a complex condition with a variable phenotype. Although pregnancy has not been previously reported in a patient with SLOS, mild cases may be under-ascertained. Our patient had mild physical anomalies of SLOS without cognitive abnormalities. The presence of LDLR polymorphisms in our patient may have a modulating role in cholesterol biogenesis and as such resulted in an attenuated biochemical and clinical phenotype.

In 2011, a report published by the National Heart, Lung, and Blood Institute on pediatric cardiovascular health and risk reduction put forth a recommendation for universal lipid screening in children and adolescents between the ages of 9 and 11 (1). Although the American Academy of Pediatrics, the National Lipid Association, and the American Heart Association have supported this recommendation, there has been substantial debate questioning this approach. Fuel was added to the fire in this debate when in August of this year the US Preventive Services Task Force (USPSTF) issued a report on childhood dyslipidemia, concluding there is insufficient evidence either in support of or against universal lipid screening in children and adolescents (2). A recent article published in Science entitled “Cholesterol screening for kids …

There is clear pathologic evidence that the process of atherosclerotic cardiovascular disease (CVD)2 begins in childhood with the deposition of fatty streaks within the arterial walls and subsequently progresses into fibrous plaques throughout adolescence and early adulthood. This evidence has generated a substantial interest outside of primary and secondary CVD prevention and a focus toward primordial prevention. The recent National Heart, Lung, and Blood Institute (NHLBI) Expert Panel on Integrated Guidelines for Cardiovascular Health and Risk Reduction in Children and Adolescents updated recommendations for the identification, management, and treatment of all major cardiovascular risk factors in pediatrics (1). These guidelines, which have also been endorsed by the American Academy of Pediatrics (AAP), address issues related to nutrition, physical activity, tobacco, high blood pressure, lipids, obesity, and the metabolic syndrome. One major challenge of this integrated approach is accounting for the fact that the manifestation of CVD typically occurs later in life and a variety of environmental factors influence the progression or attenuation of risk. One updated NHLBI recommendation that is likely to cause controversy is the recommendation of universal screening for dyslipidemia by the age of 9–11 years and subsequently at an age of 17–21 years. Lipid screening should be performed with either a fasting lipid panel [total cholesterol, HDL cholesterol (HDL-C), triglycerides, non–HDL-C, LDL cholesterol (LDL-C)] or a nonfasting lipid panel (total cholesterol, HDL-C, non–HDL-C). Initiatives and research emerging over the past 2 decades have led to a variety of approaches and attitudes toward screening for pediatric dyslipidemias, which have produced conflicting recommendations and variations in clinical practice. In 1992, the National Cholesterol Education Program first recommended a tiered approach to pediatric lipid screening, in which a fasting lipid profile was recommended if the child had a positive family history of premature CVD or dyslipidemia, had an unknown …

Objective To evaluate biomarkers of renal tubulointerstitial damage and function in type 1 diabetes with and without diabetic kidney disease. Research design and methods Cross-sectional case-control study of Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications Study participants. Cases (N=43) had incident persistent estimated glomerular filtration rate (eGFR) 300 mg/24 hour. Controls (N=43) had persistent eGFR >90 mL/min/1.73 m2 and urinary albumin excretion

Objectives To define whether the high sensitivity cardiac troponin T (hs-cTnT) assay in patients with immunoglobulin light chain amyloidosis (AL) improves risk prediction. Background Cardiac involvement is the major cause of death in patients with AL amyloidosis. Risk stratification is facilitated by cardiac biomarkers such as cardiac troponin T (cTnT) and N-terminal pro B-type natriuretic peptide (NT-proBNP). Methods Stored serum from patients with newly diagnosed AL was used to measure hs-cTnT, cTnT, and NT-proBNP. Survival modelling was performed. Results The direct numeric result from hs-cTnT measurement cannot merely be substituted for a cTnT measurement in the Mayo AL staging system. The performance of the receiver operator curve derived an hs-cTnT cut-point of 54 ng/L which improves on the value of 35 ng/L validated with the prior iteration of the assay. An alternate staging option using hs-cTnT alone—using the two thresholds 14 ng/L and 54 ng/L—performs as well as either the original Mayo AL staging system or other systems incorporating hs-cTnT. On multivariate analysis, an hs-cTnT alone staging system was independent of period of diagnosis, type of therapy, and NT-proBNP value, the last of which dropped out of the model. Alternate models were explored, but none performed better than the original system or the new hs-cTnT system. Thus, hs-cTnT can be used alone for the staging of disease prognosis. Conclusions A survival model based on hs-cTnT improves the prognostic staging of patients with AL amyloidosis, relegating NT-proBNP to a measure of cardiac response.

Cardiac troponin assays have evolved substantially over 20 years, owing to the efforts of manufacturers to make them more precise and sensitive. These enhancements have led to high-sensitivity cardiac troponin assays, which ideally would give measureable values above the limit of detection (LoD)4 for 100% of healthy individuals and demonstrate an imprecision (CV) of ≤10% at the 99th percentile. Complete integration and proper use of high-sensitivity cardiac troponin assays into clinical practice will be an important step forward for the diagnosis of myocardial infarction and will allow cardiologists to use cardiac troponin as a prognostic indicator for risk-based outcomes assessment. As laboratorians, we wish to comment on the recently published “ACCF 2012 Expert Consensus Document on Practical Clinical Considerations in the Implementation of Troponin Elevations” (1). Our purpose is to address 8 analytical issues that we believe have the potential to cause confusion and that therefore deserve clarification. Input from the field of laboratory medicine is important for emphasizing our role as analytical-content experts in the process of strengthening our collaborative relationships with various clinical societies. Since the initial publications by the National Academy of Clinical Biochemistry (NACB) in 1999 and by the European Society of Cardiology/American College of Cardiology in 2000, when both organizations endorsed cardiac troponin I (cTnI) or cTnT as the preferred biomarker for the detection of myocardial infaction, numerous other organizations have followed suit and promoted the sole use of cardiac troponin in this clinical application. The American College of Cardiology Foundation (ACCF) 2012 Expert Consensus Document (1) summarizes the recently published 2012 Third Universal Definition of Myocardial Infarction by the Global Task Force (2), thus providing some practical recommendations on the use and interpretation of cardiac troponin in clinical practice. The integration and acceptance of cardiac troponin testing over the past 13 years has …

The frequency and characteristics of patients with critical lactate values (4.0 mmol/L) is unknown.The laboratory database was reviewed for adult patients with non-point of care lactate values over a 6-month period.There were 6914 lactate values, including 625 (9.0%) critical values. Medical records were reviewed in 100 patients with critical and non-critical lactate values. Patients with critical vs. non-critical values had more metabolic acidosis (n=70/100 vs. 22/100, p0.01), hypotension or tachycardia (n=62/100 vs. 29/100, p0.01), and a higher 1-month mortality (n=42/100 vs. 7/100, p0.01). Few patients (n=10/100) with a critical value were not in the emergency department or intensive care unit.Critical lactate values are associated with a longer duration of hospitalization and increased mortality. However, the incremental value of critical lactate values was low, as most patients had abnormal vital signs and laboratory parameters. Requiring notification of lactate values4.0 mmol/L would be unlikely to augment clinical care.

Rheumatoid arthritis (RA) is an inflammatory autoimmune disease characterized by chronic joint inflammation and extra-articular manifestations, eventually leading to permanent disability without early therapeutic interventions.The analytical and clinical performance of an electrochemiluminescent immunoassay (ECLIA) (Roche Diagnostics, Indianapolis, IN) were determined for cyclic citrullinated peptide antibodies (anti-CCP) in the diagnostic assessment of rheumatoid arthritis compared to a plate-based anti-CCP enzyme immunoassay (EIA) (Inova Diagnostics, Inc.).Imprecision studies on the automated Roche ECLIA demonstrated intra-assay CV's of3% and inter-assay CV's of7%. The Inova EIA had intra-assay CV's of15% and inter-assay CV's of12%. The limit of quantitation of both assays was acceptable, and both assays showed similar linearity within the manufacturer's defined reportable ranges. Overall, analytical concordance was 62%, with 95.2% positive and 53.2% negative concordance. The clinical specificity in a normal population (n=91) was 98.9% and 100% for Roche ECLIA and Inova EIA, respectively. The clinical specificity in a connective tissue disease population (n=98) was 91.9% (95%CI, 86.0 to 96.5%) and 88.8% (95% CI, 81.0 to 93.6%) for Roche ECLIA and Inova EIA, respectively.The Roche ECLIA demonstrated similar analytical performance, although with improved intra-assay precision, in comparison to the Inova EIA. The two methods also demonstrated similar clinical sensitivity and specificity. The Roche automated immunoassay is a viable alternative to the plate-based EIAs with the advantage of being performed on an automated platform.

Tangier disease is a very rare autosomal recessive inherited disorder characterized by markedly reduced high-density lipoprotein (HDL) levels, characteristic large, yellow–orange tonsils, and enlarged liver, spleen and lymph nodes. It is caused by mutations in the ABCA1 gene. There is no specific treatment, and medications traditionally used to increase HDL are ineffective. A number of patients with non-classical Tangier disease have been described in the literature, who presented with low HDL levels, corneal lesions, hepatosplenomegaly, and thrombocytopenia. We report here about a 45-year-old female with a past medical history of early coronary artery disease, myocardial infarction, multiple episodes of angina, immeasurable HDL, and a history of idiopathic thrombocytopenia purpura. She had a tonsillectomy performed previously, but did not remember if the tonsils were of any unusual color. There was no history of peripheral neuropathy. Her family history is significant for her father and mother having Alzheimer disease and hypertension, respectively. On physical examination she did not have any hepatosplenomegaly or corneal opacities. She was found to have three mutations in the ABCA1 gene. These were designated A1046D (c.3137C>A) in exon 22; Y1532C (c.4595A>G) in exon 34, and W1699C (c.5097G>T) in exon 37. All three have been reported to be deleterious in functional studies. The patient has immeasurable HDL, which leads us to assume that two mutations are on one allele and one mutation on the other. We suspect that this condition is under-diagnosed, and as more patients are reported in the literature, the phenotype of Tangier disease will be elucidated further.

Summary Background The Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation was developed using both CKD and non-CKD patients to potentially replace the Modification of Diet in Renal Disease (MDRD) equation that was derived with only CKD patients. The objective of our study was to compare the accuracy of the MDRD and CKD-EPI equations for estimating GFR in a large group of patients having GFR measurements for diverse clinical indications. Design, setting, participants, and measurements A cross-sectional study was conducted of patients who underwent renal function assessment for clinical purposes by simultaneous measurements of serum creatinine and estimation of GFR using the MDRD and CKD-EPI equations and renal clearance of iothalamate (n = 5238). Results Bias compared with measured GFR (mGFR) varied for each equation depending on clinical presentation. The CKD-EPI equation demonstrated less bias than the MDRD equation in potential kidney donors (−8% versus −18%) and postnephrectomy donors (−7% versus −15%). However, the CKD-EPI equation was slightly more biased than the MDRD equation in native CKD patients (6% versus 3%), kidney recipients (8% versus 1%), and other organ recipients (9% versus 3%). Among potential kidney donors, the CKD-EPI equation had higher specificity than the MDRD equation for detecting an mGFR Conclusions Clinical presentation influences the estimation of GFR from serum creatinine, and neither the CKD-EPI nor MDRD equation account for this. Use of the CKD-EPI equation misclassifies fewer low-risk patients as having reduced mGFR, although it is also less sensitive for detecting mGFR below specific threshold values used to define CKD stages.

OBJECTIVES: Secretin pancreatic function tests play an important role in the diagnosis of chronic pancreatitis. Back titration is the standard method for measurement of bicarbonate in pancreatic juice but is time consuming and manually performed. Use of an autoanalyzer for this purpose is not validated. METHODS: Bicarbonate concentrations in secretin-stimulated pancreatic juice specimens were quantitated by manual back titration, a clinical chemistry autoanalyzer (automated bicarbonate, Roche Cobas c501, Roche Diagnostics, Indianapolis, Ind), and a blood gas analyzer (calculated bicarbonate, GEM 3000, Instrumentation Laboratories, Bedford, Mass). Kappa statistic analysis, Bland-Altman analysis, and Lin concordance correlation coefficients were calculated. RESULTS: Ninety specimens from 31 subjects were included. Using a bicarbonate concentration of 80 mEq/L as a cutoff value, there was poor agreement between back titration and calculated bicarbonate (κ = 0.188); however, only 1 specimen showed discrepancy between back titration and automated bicarbonate (κ = 0.977). The limit of agreement between the back titration and automated bicarbonate was -9.0 to + 8.3 mEq/L. The Lin concordance correlation coefficient between the 2 methods was 0.931 (P < 0.001). CONCLUSIONS: There is strong concordance between manual back titration and chemistry autoanalyzer methods for measurement of bicarbonate concentrations in pancreatic juice. Autoanalyzers may replace back titration for this purpose. Blood gas analyzers are unsuitable.

The advent of inexpensive, highly accurate, and predictive markers of myocardial injury, inflammation, and hemodynamic stability has revolutionized the evaluation and treatment of patients who have acute coronary syndromes (ACSs). These blood biomarkers require small sample volumes, can be run expeditiously, and provide important information concerning the diagnosis, risk stratification, and treatment of these patients. To understand the use of these markers, one must have some knowledge about what elevations in these markers imply, how they have to be collected and measured to provide reliable information, when to suspect analytic confounds, and what the key values are that impart the diagnostic, prognostic, and therapeutic information. This article discusses these issues, emphasizing what clinicians must know for optimal test use, and then addresses the practical use of these markers in patients who have ACS.

BACKGROUND This study uses the Isotope Dilution Mass Spectrometer-Traceable Modification of Diet in Renal Disease (MDRD) equation to evaluate the effects of analytic variation of serum creatinine on estimated glomerular filtration rate (eGFR). The equation was inverted to provide critical creatinine levels corresponding to eGFRs equal to 15, 30, and 60 mL/min/1.73 m(2). METHODS eGFRs were calculated for two populations of patients representing clinic outpatients and hospitalized inpatients. Simulation studies evaluated the effects of analytic bias for these populations. Differences between creatinine tests ordered on consecutive blood draws were analyzed for within-subject eGFR variation. Finally, propagation of error techniques established the relationship between creatinine imprecision and eGFR imprecision. RESULTS eGFR of 60 mL/min/1.73 m(2) corresponds to creatinine levels of 80-156 micromol/L. A 20-micromol/L negative shift of creatinine approximately doubles the percentage of patients classified in various stages of decreased renal function, whereas a positive shift approximately halves the percentage. The central 95% limits for within-subject variation of eGFR are 33% for outpatients, 38% for inpatients and 40% across the groups. eGFR imprecision is approximately 15%-20% higher than creatinine imprecision. CONCLUSIONS Small analytic changes in serum creatinine create major shifts in the distributions of eGFR, which can cause large differences in the classification of patients. The within-subject variations in eGFR over time, especially between hospital and clinic measurements, can be large. Therefore, tight control of laboratory analysis is important.

Background: The International Staging System for multiple myeloma has increased the importance of accurate measurement of serum albumin. Two common albumin assays, bromcresol green (BCG) and agarose gel protein electrophoresis (PEL), frequently yield discordant results, creating confusion regarding which assay is superior for use in myeloma. Methods: We measured albumin by BCG on a Roche Modular system, by PEL with a Helena SPIFE SPE Vis agarose gel, and by immunonephelometry performed on a Dade Behring BNII nephelometer. BCG and PEL were used to measure albumin in 5777 patient samples, and all 3 methods were used in an additional 252 samples. The clinical impact was assessed on 698 myeloma patient samples. Results: For sera with zero/low monoclonal immunoglobulin protein (M)-spike (0 to Conclusions: Both BCG and PEL correlate well to nephelometry in sera with zero/low M-spikes. In the presence of larger M-spikes, PEL correlates poorly to nephelometry or BCG, whereas BCG compares well with nephelometry regardless of M-spike. Thus, albumin measurement can be performed reliably in myeloma patient sera by use of inexpensive, automated BCG assays.

To the Editor: Cardiac troponin is the marker of choice for evaluating myocardial injury (1). High-sensitivity assays improve analytical detection limits, thereby allowing concentrations to be measured in the majority of healthy individuals. This capability allows an assessment of biologic variation (BV)1 to determine what constitutes a clinically important change in the cardiac troponin concentration, a critical metric for identifying acute events. Such an event is often a myocardial infarction, but any acute cardiac injury can cause increasing and/or decreasing values (1). Accordingly, we evaluated BV for a recently developed high-sensitivity cardiac troponin I (hs-cTnI) assay (2) from Beckman Coulter. We performed this study with the same cohort used to define BV for the high-sensitivity cardiac troponin T (hs-cTnT) assay (3) and according to a protocol approved by our institutional review board. For assessment of short-term BV, we collected blood into serum separator tubes (Becton Dickinson) at 0, 1, 2, 3, and 4 h, centrifuged the tubes, and stored the serum samples immediately at −70 °C. …

Background It is uncertain which acute phase reactant, C-reactive protein (CRP) or erythrocyte sedimentation rate (ESR) correlates best with disease activity in patients with systemic lupus erythematosus (SLE). Objectives The objective of this study was to determine which acute phase reactant correlated best with disease activity in patients with SLE. Methods All patients enrolled met American College of Rheumatology classification for SLE and were evaluated by rheumatologists. All patients had simultaneous measurement of CRP, high sensitivity CRP (hsCRP), and ESR. CRP and hsCRP were analyzed on the Roche Modular System, and ESR was measured by the Westergren method. Disease activity assessment was done by SLEDAI score. Results Of 80 patients enrolled, 65 were female (81%) and the mean age of the patients was 46.6 years (range 23 to 79). 56 patients (70%) had active disease defined as SLEDAI score >0. The mean CRP was 5.4 mg/L (range 8 mg/L). hsCRP was measured in the first 49 subjects enrolled in the study. The mean hsCRP was 4.2 mg/L (range 0.17 to 30.1, median 2.42) with 6 elevated values (4 corresponding to abnormal CRP values and 2 additional). The mean ESR was 17.6 mm/1 hr (range 1-95, median 13) with 16 elevated values (>22 for males, >29 for females). Both ESR and CRP were significantly correlated with SLEDAI scores (r=0.22, p=0.046, and r=0.37, p Elevated ESR was significantly associated with higher SLEDAI scores (p=0.002 by rank sum test) as was elevated CRP (p=0.03). Patients that had an elevated ESR, elevated CRP or both had significantly higher SLEDAI scores than those with normal ESR/CRP (p=0.002). By use of linear regression models, ESR and CRP were found to be independently associated with SLEDAI scores (ESR p=0.01; CRP p ESR was elevated in 14/56 (25%) patients with active lupus while CRP was elevated in 8/56 (14%) patients. ESR was more likely to be elevated in active disease than CRP (p=0.10). However, 18/56 (32%) patients that had active disease had either an elevated CRP, ESR or both. Only 4 (17%) of the 24 patients with inactive lupus had elevation in CRP or ESR. Conclusions ESR was more likely to be elevated in active lupus than CRP. However, both correlated with disease activity and neither were elevated in all patients with active disease. Additional measurement of hsCRP was not helpful. In lupus patients who have a normal ESR and normal CRP, active disease is still common. References Feldman M, Aziz B, Kang GN, Opondo MA,Belz RK, Sellers C: C-reactive protein and erythrocyte sedimentation rate discordance: frequency and causes in adults. Journal of Laboratory and Clinical Medicine 161(1):37-43, 2013 Jan. Amezcua-Guerra LM, Springall R, Arrieta-Alvarado AA, Rivera-Martinez E, Castillo-Martinez D, Bojalil R: C-reactive protein and complement components but not other acute phase reactants discriminate between clinical subsets and organ damage in systemic lupus erythematosus. Clinical Laboratory 57(7-8):607-13, 2011. Disclosure of Interest None declared DOI 10.1136/annrheumdis-2014-eular.1073

The use of soluble cardiac biomarkers such as NT-proBNP and troponin has revolutionized prognostication for patients with AL amyloidosis and led to their use in the Mayo 2004 and 2012 staging systems. Novel soluble markers with different phenotypic targets may further improve this approach. Soluble ST2 (sST2), which is the circulating form of the IL-33 receptor, has been shown to be a marker of cardiac remodelling and fibrosis, is predictive of mortality in patients with congestive heart failure, and is predictive of risk of GVHD and GVHD mortality. Samples of blood of patients with AL amyloidosis collected and frozen at -20C under a biobank IRB protocol were retrieved and sST2 measured. Patients were eligible for present study if they had a research sample collected within 90 days of their AL amyloidosis diagnosis. We have validated that values do not change significantly with storage at -20C over a 90 day period. Concentrations of sST2 were determined using a novel high-sensitivity sandwich immunoassay (Presagew ST2; Critical Diagnostics, San Diego, CA, USA). The sST2 assay had within-run and total coefficients of variation of A larger cohort including patients with longer follow up will be presented at the meeting as will gender specific cut off values and a comparison of our values with those previously used to prognosticate in patients with heart failure. sST2 appears to be a novel powerful prognostic factor for patients with AL amyloidosis. Because sST2 functions as a decoy receptor, which neutralizes the benefits of IL-33, it may play a role in the deleterious phenotype seen in patients with AL, i.e. myocardial hypertrophy and reduction of contractility. Disclosures: Saenger: Critical Diagnostics : Research Funding; Roche: Research Funding. Jaffe:Critical Diagnostics: Consultancy, Research Funding; Roche: Consultancy.

Altered concentrations of bile acid (BA) in the colon can cause diarrhea or constipation. More than 25% of patients with irritable bowel syndrome with diarrhea or chronic diarrhea in Western countries have BA malabsorption (BAM). As BAM is increasingly recognized, proper diagnostic methods are needed to help direct the most effective course of treatment for the chronic bowel dysfunction. We review the methodologies, advantages, and disadvantages of tools that directly measure BAM: the (14)C-glycocholate breath and stool test, the (75)selenium homotaurocholic acid test (SeHCAT), and measurements of 7 α-hydroxy-4-cholesten-3-one (C4) and fecal BAs. The (14)C-glycocholate test is laborious and no longer widely used. The (75)SeHCAT has been validated but is not available in the United States. Measurement of serum C4 is a simple and accurate method that can be used for most patients but requires further clinical validation. Assays to quantify fecal BA (total and individual levels) are technically cumbersome and not widely available. Regrettably, none of these tests are routinely available in the United States; assessment of the therapeutic effects of a BA binder is used as a surrogate for diagnosis of BAM. Recent data indicate the advantages to studying fecal excretion of individual BAs and their role in BAM; these could support the use of the fecal BA assay, compared with other tests. Measurement of fecal BA levels could become a routine addition to the measurement of fecal fat in patients with unexplained diarrhea. Availability ultimately determines whether the C4, SeHCAT, or fecal BA test is used; more widespread availability of such tests would enhance clinical management of these patients.

Background: Idiopathic bile acid malabsorption (BAM) causes chronic diarrhea and BA deficiency may cause constipation. BA supplementation and an ileal BA transporter inhibitor, elobixibat, accelerate colonic transit (CT). Rectal infusion of BA (e.g. chenodeoxycholate) induces colonic propulsive motility. Up to 50% of patients with IBS-D have accelerated CT; 20% of patients with IBS-C have delayed CT. The relationship between fecal BA excretion, CT, and bowel symptoms in IBS is unclear and may be relevant to selecting optimal therapy. Aim: To assess stool frequency (number) and consistency (form) in relation to CT and fecal BA excretion in healthy participants and patients with IBS-C and IBS-D. Methods: In a prospective study of 92 participants (31 healthy, 30 IBS-C and 31 IBS-D by Rome III criteria), we measured total and individual fecal BA and fecal fat (on 100g fat diet), overall CT by validated scintigraphy (geometric center, GC at 24 and 48h) and stool characteristics by a 14 day bowel pattern diary including Bristol stool form scale. Univariate associations between endpoints were assessed using Spearman correlation (rs). Relationships between stool characteristics, CT and fecal BA excretion were assessed using response surface multiple regression models (which included BMI as a covariate and linear, quadratic and cross product terms for the CT and BA measurements). Results: 1. There were significant univariate associations (table showing rs) between stool number and stool form and total fecal BA (including % LCA, % CDCA, and % CA), fecal fat, and GC24 and 48. 2. The response surface model for stool number (figure left panel) with total fecal BA and CT (GC24 ) explained 29% of the variation (r=0.54, p,0.001); similarly, the model for stool form (figure middle panel) with fecal BA and CT (GC24) explained 20% of the variation (r=0.45, p=0.021). Using total secretory BA (CA+DCA+CDCA), the response surface model for stool form (figure right panel) explained 23% of the variation (r=0.49, p=0.006). In these models, the relative contribution of CT was consistently greater than that for BA, with the coefficients corresponding to CT being statistically significant (p,0.05), while those for BA were borderline (e.g. p=0.073 for the coefficient for secretory BA and stool form, and p=0.227 for stool number). Conclusion: Relative to fecal BA, colonic transit is the greater determinant of stool number and stool form; increased total and secretory fecal BA enhance the effects of colon transit on stool characteristics, but are not independently significant factors. Funding:NIHDK92179