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Background Using middleware solutions, it is possible to implement concentration-dependent analyte-specific hemolysis rejection limits. This makes day-to-day reporting of clinical specimens more efficient and potentially lowers sample rejection rates compared to a “one-size-fits-all” approach (i.e., solely based on a single cutoff provided in the package insert). Methods Hemolysis interference studies were performed at multiple analyte concentrations for three frequently ordered tests. For each assay, concentration-dependent hemolysis rejection limits were designed based on the total allowable error (TAE) for the analyte as well as the clinical significance of such incurred inaccuracy at the respective concentrations. In general, the following rationale was used: if the interference exceeds 10% (or package insert cutoffs), a comment is placed on the result. If the interference exceeds the TAE, the result will not be reported. Reduction in specimen rejection rates were estimated by comparing the incurred specimen rejection rates when package inserts’ vs concentration-dependent hemolysis interference limits were applied to a data set in our institute during a three-month period. Results Concentration-dependent analyte-specific hemolysis rejection thresholds were designed for three commonly ordered assays that are especially susceptible to hemolysis interference. It is estimated that these novel thresholds for aspartate aminotransferase (AST), lactate dehydrogenase (LDH), and direct bilirubin (DBIL) reduced specimen rejection rates from 9.3% to 1.3%, 31.4% to 4.8%, and 19.9% to 7.1%, respectively. Conclusions Concentration-dependent analyte-specific hemolysis rejection thresholds for three commonly ordered assays can reduce rejection rates without significantly compromising the quality of test results.

Objectives We sought to replace the highly hemolysis-susceptible diazo conjugated bilirubin (Bc) assay with the more robust vanadate oxidation method and determine its impact on test cancellation in the pediatric population. Methods Analytical validation of the Randox vanadate assay and comparison with the Roche diazo method were performed. The frequency of pediatric sample cancellation because of hemolysis was compared between the diazo and vanadate methods by retrospective analysis of clinical test data. Results The vanadate assay demonstrated no clinically significant interference from hemolysis up to a hemolysis index of 1,300 (approximately 13 g/L hemoglobin). There was a strong correlation with the diazo method (r2 = 0.97) but with a positive slope bias of 1.27. Implementing the vanadate method resulted in a significantly lower proportion of pediatric samples cancelled because of hemolysis compared with the diazo method (0.6% of 688 patients vs 30.6% of 10,464 patients, respectively; P < .001), with a 0.6% (n = 513) vs 43.2% (n = 6,464) reduction in test cancellations (P < .001) for children younger than 6 months of age. Conclusions The vanadate method showed robust performance against hemolysis. Its implementation resulted in a significant decrease in pediatric tests cancelled because of hemolysis.

ObjectivesTo evaluate the analytical and clinical performance of the Truvian Easy Check coronavirus disease 2019 (COVID-19) IgM/IgG anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody test.Serologic assays have become increasingly available for surveillance through the Food and Drug Administration emergency use authorization in the ongoing COVID-19 global pandemic. However, widespread application of serologic assays has been curbed by reports of faulty or inaccurate tests. Therefore, rapid COVID-19 antibody tests need to be thoroughly validated prior to their implementation.MethodsThe Easy Check device was analytically evaluated and its performance was compared with the Roche Elecsys anti-SARS-CoV-2 antibody assay. The test was further characterized for cross-reactivity using sera obtained from patients infected by other viruses. Clinical performance was analyzed with polymerase chain reaction-confirmed samples and a 2015 prepandemic reference sample set.ResultsThe Easy Check device showed excellent analytical performance and compares well with the Roche Elecsys antibody assay, with an overall concordance of 98.6%. Clinical performance showed a sensitivity of 96.6%, a specificity of 98.2%, and an overall accuracy of 98.1%.ConclusionsThe Easy Check device is a simple, reliable, and rapid test for detection of SARS-CoV-2 seropositivity, and its performance compares favorably against the automated Roche Elecsys antibody assay.

Objectives To analytically and clinically evaluate the semiquantitative Elecsys anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein antibody (S-Ab) assay on the Roche cobas e602 analyzer. Methods The S-Ab assay is a 1-step, double-antigen sandwich electrochemiluminescent immunoassay that semiquantitatively measures total IgG, IgM, and IgA antibodies specific for the receptor binding domain of SARS-CoV-2 spike protein in serum or plasma. The S-Ab assay was evaluated for precision, linearity, interference (by hemoglobin, bilirubin, triglycerides, and biotin), cross-reactivity, and clinical performance, and was compared to the qualitative Elecsys anti-nucleocapsid (N-Ab) immunoassay, a lateral flow device that qualitatively detects S-Ab and N-Ab, and an anti-spike enzyme-linked immunosorbent assay (ELISA). Results S-Ab assay is precise, exhibits linearity from 0.4 to 250 U/mL, is unaffected by significant cross-reactivity or interferences, and qualitatively demonstrates greater than 90% concordance with N-Ab assay and lateral flow device. Readouts of S-Ab assay correlate with ELISA, which in turn correlates strongly with SARS-CoV-2 virus neutralization assay, and exhibit 100% sensitivity and specificity for COVID-19 patient samples obtained at or more than 14 days after PCR positivity. Conclusions The S-Ab assay is a robust clinical test for qualitative and semiquantitative detection of seropositivity following SARS-CoV-2 infection or spike-encoding mRNA COVID-19 vaccination.

BackgroundPharmacogenomics has the potential to improve patient outcomes through predicting drug response. We designed and evaluated the analytical performance of a custom OpenArray® pharmacogenomics panel targeting 478 single-nucleotide variants (SNVs).MethodsForty Coriell Institute cell line (CCL) DNA samples and DNA isolated from 28 whole-blood samples were used for accuracy evaluation. Genotyping calls were compared to at least 1 reference method: next-generation sequencing, Sequenom MassARRAY®, or Sanger sequencing. For precision evaluation, 23 CCL samples were analyzed 3 times and reproducibility of the assays was assessed. For sensitivity evaluation, 6 CCL samples and 5 whole-blood DNA samples were analyzed at DNA concentrations of 10 ng/µL and 50 ng/µL, and their reproducibility and genotyping call rates were compared.ResultsFor 443 variants, all samples assayed had concordant calls with at least 1 reference genotype and also demonstrated reproducibility. However, 6 of these 443 variants showed an unsatisfactory performance, such as low PCR amplification or insufficient separation of genotypes in scatter plots. Call rates were comparable between 50 ng/µL DNA (99.6%) and 10 ng/µL (99.2%). Use of 10 ng/µL DNA resulted in an incorrect call for a single sample for a single variant. Thus, as recommended by the manufacturer, 50 ng/µL is the preferred concentration for patient genotyping.ConclusionsWe evaluated a custom-designed pharmacogenomics panel and found that it reliably interrogated 437 variants. Clinically actionable results from selected variants on this panel are currently used in clinical studies employing pharmacogenomics for clinical decision-making.

Background The interest for vitamin D has exponentially increased testing demand for 25-hydroxy vitamin D [25(OH)D]. Consequently, many laboratories are switching from LC-MS/MS methods to automated, high-throughput immunoassays. One of the major potential issues with these assays has been the lack of cross-reactivity with 25(OH)D2. Methods We have evaluated the Roche Elecsys vitamin D total II assay for accuracy by comparing 79 patient samples with LC-MS/MS. The cross-reactivity for 25(OH)D2 was evaluated by analyzing samples with high 25(OH)D2 separately and estimating 25(OH)D2 recovery, as well as by spiking of 25(OH)D2. The assay was further evaluated for precision, linearity, sample type, and common interferences. Results There was mostly good agreement between the Elecsys and LC-MS/MS assays (Deming regression: y = 0.95x + 0.70), with an overall bias of 2.3% (−0.84 ng/mL). However, there were 6 out of 79 (7.6%) discordant samples. The Deming regression for samples with high 25(OH)D2 compared to LC-MS/MS showed similar slope and intercept (y = 0.97x − 1.1). The average recovery of 25(OH)D2 for these samples was 90%. The initial precision studies were in general agreement with the package insert, but long-term clinical use showed higher-than-claimed imprecision (11.7%–14.4% at 12 ng/mL and 6.9%–7.6% at 27 ng/mL; claimed: 7.2% and 5.0%, respectively). We observed 1 falsely high result in plasma, an issue previously addressed by Roche in a medical device correction. Conclusions The analytical performance of the Roche Vitamin D assay was acceptable, and the assay had a good cross-reactivity for 25(OH)D2.

Objectives Thyroid hormone analog 3,5,3'-triiodothyroacetic acid (TRIAC) is effective in reducing the hypermetabolism in monocarboxylate transporter 8 (MCT8)–deficient individuals. Because of the structural similarity between TRIAC and 3,3',5'-triiodothyronine (T3), we sought to investigate the degree of cross-reactivity of TRIAC with various commercially available total and free T3 assays. Methods Varying concentrations (50-1,000 ng/dL) of TRIAC (Sigma Aldrich) were added to pooled serum and assayed for total T3 (TT3) and free T3 (FT3) on the following platforms: e602 (Roche Diagnostics), Architect (Abbott Diagnostics), Centaur (Siemens Healthcare Diagnostics), IMMULITE (Siemens Healthcare Diagnostics), DxI (Beckman Coulter), and Vitros (Ortho Clinical Diagnostics). TT3 competition assay with TRIAC was performed by adding increasing amounts of T3 to pooled serum samples that contained a constant concentration of TRIAC (250 ng/dL). Results Significant overestimation of TT3 and FT3 assays were observed across all platforms corresponding to increasing concentrations of TRIAC. The TRIAC effect at 250 ng/dL showed a constant interference of approximately 190 ng/dL TT3. Conclusions All commercial TT3 and FT3 assays tested in this work cross-react significantly with TRIAC. Therefore, patients undergoing TRIAC therapy should have T3 hormone response monitored using alternative nonimmunoassay-based methods to avoid misinterpretation of thyroid function profiles.

Objectives To evaluate the analytical and clinical performance of the automated Elecsys anti–severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody (Elecsys Ab) assay on the Roche cobas e602 analyzer. With the ongoing global coronavirus disease 2019 (COVID-19) pandemic, widespread and routine serologic testing of SARS-CoV-2 remains a pressing need. To better understand its epidemiologic spread and to support policies aimed at curtailing further infections, reliable serologic testing is crucial for providing insight into the dynamics of the spread of COVID-19 on a population level. Methods The presence of anti–SARS-CoV-2 antibodies in polymerase chain reaction–positive, confirmed COVID-19 patient samples was determined using the Elecsys Ab assay on the Roche cobas e602 analyzer. The precision and cross-reactivity of the Elecsys Ab assay were characterized and its performance was compared against the EuroImmun IgA/IgG antibody (EuroImmun Ab) assay. Calculated sensitivity, specificity, and positive and negative predictive values were assessed. Results The Elecsys Ab assay demonstrated good precision, had no cross-reactivity with other viral samples, and showed 100% concordance with the EuroImmun Ab assay. Excellent clinical performance with respect to sensitivity, specificity, and positive and negative predictive values was observed. Conclusions The Elecsys Ab assay is a precise and highly reliable automated platform for clinical detection of seropositivity in SARS-CoV-2 infection.

Background Patients with Smith-Lemli-Opitz Syndrome (SLOS) have defective endogenous cholesterol synthesis, and present with decreased cholesterol levels and multiple developmental dysmorphologies. Case description A newborn infant with normal XY karyotype and normal microarray was born with multiple developmental defects and ambiguous genitalia. The patient was diagnosed with SLOS, following biochemical genetic analysis of serum 7-DHC concentrations. The clinical course of the patient was further complicated by the comorbidities associated with SLOS and the bacterial infections. Conclusion We provide a detailed biochemical profile of the SLOS patient. The report can help us further understand the pathological impacts of cholesterol synthesis deficiency and provide relevant clinical management with outcome of this rare genetic disorder.

Novel angiogenic biomarker profiles have demonstrated emerging evidence for predicting preeclampsia onset, severity, and adverse outcomes. Limited data exist in screening patients with fetal growth restriction for preeclampsia development using angiogenic biomarkers.The objective of this study was to risk stratify patients with fetal growth restriction using a soluble fms-like tyrosine kinase-1 to placental growth factor ratio. Previously published cutoff of 38 was used to predict preeclampsia development and severity as well as adverse maternal or neonatal outcomes within a 2-week time period.This was a prospective observational cohort study performed in a single tertiary hospital. Patients with a singleton fetal growth restriction pregnancy between 24 and 37 weeks' gestation were evaluated using serial 2-week encounters from the time of enrollment to delivery. Pregnancies with proven genetic or infectious etiology of fetal growth restriction or congenital anomalies were excluded. Ultrasound growth and Doppler measurements were obtained at the start of every encounter with routine preeclampsia laboratory tests and blood pressure checks when clinically indicated. Maternal serum was collected for all serial encounters and measured for soluble fms-like tyrosine kinase-1 and placental growth factor after delivery in a double-blinded fashion. Maternal charts were reviewed for baseline demographic characteristics, pregnancy diagnoses and outcomes, and neonatal outcomes.A total of 45 patients were enrolled for a total of 77 encounters, with the median (quartile 1, quartile 3) gestational age of the study enrolled at 31.43 (28.14-33.57) weeks. Patients were divided into low-risk (ratio of38) and high-risk (ratio of ≥38) groups. Baseline characteristics of patients did not show any marked differences, including preeclampsia labs or ultrasound parameters, between the 2 groups. Systolic and diastolic blood pressures upon enrollment were statistically elevated when soluble fms-like tyrosine kinase-1 to placental growth factor ratio was ≥38 (P=.02 and P=.01, respectively). Compared to patients with a low ratio, patients with a high ratio had a greater proportion of preeclampsia diagnosis, higher rates of preterm delivery under 34 and 37 weeks gestation, smaller neonatal birthweight, and a shorter time to delivery from testing to delivery.Among patients with fetal growth restriction, the soluble fms-like tyrosine kinase-1 to placental growth factor ratio may serve as a potential biomarker for identifying at risk patients for developing preeclampsia and subsequently preterm delivery.

Background CYP2D6 is involved in the oxidative metabolism of approximately 20% of all clinically used medications. Genotyping cytochrome P450, family 2, subfamily D, polypeptide 6 (CYP2D6), is a challenge because of the high complexity of the locus. Methods Twenty-nine CYP2D6 sequence variants were genotyped in 50 deidentified patient samples and 29 Coriell DNAs by Invader assay, and results were compared with Infiniti assay and Sanger sequencing. To determine CYP2D6 copy number, 3 TaqMan real-time hydrolysis probes were used and results were compared with long-range PCR. Discrimination of the duplicated alleles was done on 17 DNA samples with 3 copies of CYP2D6 by long-range PCR followed by Invader genotyping and single nucleotide extension for the comparison. Results Complete concordance was observed for all samples between platforms except for 2 samples due to the lack of the *45 allele in the Infiniti panel. Reproducibility with the Invader assay and TaqMan copy number was 100%. Analytical sensitivity using DNA with 2 copies was determined to be 10 ng DNA for the Invader assay and 1 ng/μL DNA for the TaqMan assay, respectively. Complete concordance and reproducibility were observed for duplicated allele discrimination with the exception of 1 sample, determined to be *29/*43X2 by the Invader test and *1X2/*29 by the Infiniti method, which did not test for *43. Conclusions This validation study showed that Invader and TaqMan assay combined panel provides an attractive, valid, highly accurate, and reproducible approach for CYP2D6 genotyping for clinical implementation.

Background Preeclampsia is a leading hypertensive disorder in pregnant women. The angiogenic biomarkers, soluble fms-like tyrosine kinase-1 (sFlt-1) and placental growth factor (PlGF) ratio, have been shown to be associated with diagnosis and prediction of preeclampsia. The objective of this study is to validate the analytical performance of sFlt-1 and PlGF on the Cobas e602 system (Roche Diagnostics Corporation). Method Intra-day and inter-day precisions for both sFlt-1 and PlGF assays were assessed using quality control materials provided from Roche Diagnostics. The accuracies for both assays were assessed by running 60 patient samples, which have been previously analyzed on the Elecsys 411 analyzer (Roche Diagnostics Corporation) at the Beth Israel Deaconess Medical Center. Linearity studies for both assays were performed using patient plasma spiked with recombinant sFlt-1 and PlGF proteins (R&D systems). Hemolysis, icterus, lipemia and biotin interference studies were performed by spiking hemolysate, bilirubin, intralipid or biotin into either pooled patient plasma with detectable levels of sFlt-1 and PlGF or otherwise, patient plasma spiked with recombinant sFlt-1 and PlGF proteins. Results Total precisions for both assays demonstrated CVs of 0.98). Lower limit of quantitation (10% CV) was 30 pg/mL for sFlt-1 and 7 pg/mL for PlGF, respectively. Interference studies showed sFlt-1 and PlGF were not significantly affected by hemolysis up to H-indices of 500 and 1000 respectively; both assays were not affected by bilirubin up to an I-index of 60, and lipemia up to an L-index of 2800. Biotin at concentrations >30 ng/mL caused significant negative bias for both sFlt-1 and PlGF assays. Comparison studies showed the following: Cobas e602 sFLT-1 = 1.09 [Elecsys 411 sFLT-1] +203 (r2=0.97, Sy/x=1234, n=58); Cobas e602 PlGF = 1.10 [Elecsys 411 PlGF] +47 (r2=0.99, Sy/x=22.1, n=58); Cobas e602 sFLT-1/PlGF ratio = 0.94 [Elecsys 411 sFLT-1/PlGF ratio] +3.5 (r2=0.91, Sy/x=50, n=58). Conclusion sFlt-1 and PlGF measured on Roche Diagnostics Cobas e602 system demonstrated excellent analytical performance and are acceptable for clinical use once approved in the US.

Objectives Analysis of platelet functional responses to stimuli is presently quite limited with respect to measurement of dense granule secretion. We sought to develop a nonradioactive assay of stimulated serotonin release using liquid chromatography tandem mass spectrometry (LC-MS/MS). Methods Citrated whole blood (200 μL) was incubated with deuterated serotonin (d45-HT). Following uptake by platelets, blood was diluted 10-fold and aliquots were incubated with platelet stimuli. Following stimulation, blood was further diluted, centrifuged, and supernatant was assayed for released d45-HT by micro-LC–MS/MS. Results This study demonstrated a broad linear range of 50 to 2,000 pg/mL d45-HT, with a total precision of less than 15.0% coefficient of variation at all quality control levels and a limit of quantitation of 50 pg/mL. Conclusions Quantification of d45-HT by micro-LC–MS/MS assay offers a highly sensitive, nonradioactive methodology for quantitating platelet serotonin uptake and dense granule secretion, requiring only small volumes of patient blood.

Background There are considerable demands to accurately measure estradiol (E2) at low concentrations ( Methods A total of 290 μL of sample was mixed with internal standard (IS), E2-d4, and extracted with a mixture of hexane/ethyl acetate (90/10) (v/v). After extraction, sample was separated by Eksigent Ekspert™ micro LC 200 system with a flow rate of 35 μL/min in a total run time of 3.5 min and detected by SCIEX QTRAP 6500 mass spectrometer in a negative mode using transitions: 271/145 (quantifier) and 271/143 (qualifier). In this method, it was crucial to use HPLC columns with stability at a pH >10. Results The validation study demonstrated broad linear ranges (3.0–820.0 pg/mL) with r 2 > 0.999. Total precision was below 15% at all QC levels, and limit of quantification (LOQ) was 3.0 pg/mL. Our method showed good correlation with E2 RIA (r 2 = 0.96, bias = −1.0 pg/mL) and modest correlation with E2 Roche Cobas automated immunoassay (r 2 = 0.86, bias = 6.0 pg/mL). Conclusions In conclusion, we developed and validated a routinely applicable micro LC-MS/MS method without derivatization for E2 in blood samples with an LOQ of 3.0 pg/mL.

Background We compared the rates of intraoperative parathyroid hormone (PTH) decline using the Siemens Immulite® Turbo PTH and Roche Elecsys® short turnaround time PTH assays in 95 consecutive surgical patients to investigate analytical and turnaround time (TAT) differences between the tests performed in the operating room (OR) vs the central clinical chemistry laboratory (CCL). Methods Serial blood samples from 95 patients undergoing parathyroidectomy were collected and measured using the 2 immunoassays. Specimens from the first 15 patients were measured simultaneously in the OR and CCL and used for the TAT study. In addition to 2 baseline samples, specimens were collected at 5, 10, and 15 min (for some patients, >15 min) after parathyroidectomy. Results In the TAT study, a significant difference was observed (OR median 20 min vs CCL median 27 min; P < 0.05). Of the 95 patient series, slower rates of parathyroid hormone decrease were observed in approximately 20% of the patients when comparing the Roche with the Immulite immunoassay. Conclusions There was a slightly longer TAT in the CCL compared with running the assay directly within the OR (median difference of approximately 7 min). For a majority of the patients, both methods showed equivalent rates of PTH decline; however, for approximately 20% of the patients, there was a slower rate of PTH decline using the Roche assay.

Background Delivery of cytotoxic therapy is a complex multifaceted process that involves harmonized collaboration between all systems involved. Optimizing laboratory turnaround time (TAT) ensures timely delivery of chemotherapy, which potentially translates into improved patient outcomes and satisfaction. In this study, we aimed to reduce the laboratory TAT for key laboratory tests to optimize the timely administration of chemotherapy. Methods TAT data for complete blood count (CBC) and comprehensive metabolic panel (CMP) included specimen collection to receipt (Col-Rcv), specimen receipt to result release (Rcv-Res), and the overall TAT from specimen collection to result release (Col-Res). Work flows were reconfigured to transport CBC specimens directly to the hematology laboratory after collection and to treat all CMP samples from chemotherapy clinics as urgent [i.e., shortest turnaround time (STAT)]. From the CMP, total bilirubin and creatinine—the 2 key analytes for liver and renal toxicity assessment before chemotherapy drug administration—were analyzed on ABL 800 whole blood analyzers to further improve the laboratory TAT. Results CBC showed a significant reduction in the median (Col-Res) TAT to 16 min (P < 0.0001). For CMP, by processing all specimens as STAT samples, the median (Col-Res) TAT was reduced from 74 min to 54 min (P < 0.0001), and it was further reduced to 9 min (P < 0.0001) for total bilirubin and creatinine. Conclusion Careful work flow analysis and reengineering of preanalytical and analytical process for key laboratory tests significantly reduced median overall TAT to

Background The anti-tumor necrosis factor alpha (TNFα) therapeutic monoclonal antibodies (mAbs), such as adalimumab, are widely used in the treatment of rheumatoid arthritis, inflammatory bowel diseases, and other auto-immune diseases. The administration of adalimumab can elicit the immune responses from some patients, resulting in the formation of anti-drug antibodies (ADAbs). The ADAbs can diminish the therapeutic effects of adalimumab by neutralizing the TNFα binding site or increasing its clearance from circulation. Methods To effectively monitor the therapeutic concentrations of adalimumab, we developed and validated a targeted quantitative proteomic assay to determine the circulating concentrations of adalimumab. Since drug effects can be attenuated by ADAbs, the method adopted an affinity-enrichment step to selectively quantify the bioavailable forms of adalimumab in patient serum samples. Results The performance of the LC–MS/MS based assay provides the analytical measuring range and precisions applicable for the therapeutic monitoring of adalimumab. It also provides comparable results to a cell-based activity assay when evaluating patient samples with different concentrations of adalimumab. Conclusion Our assay can quantify both sub-therapeutic and therapeutic concentrations of bioavailable adalimumab in patient serum samples. This assay design provides an alternative to isotope-labeled peptides approach currently adopted in targeted proteomics methods.

Background An offsite satellite clinic of the University of Chicago Medical Center (UCMC) requested an investigation by the Clinical Chemistry Laboratory (CCL) into several cases of possible falsely elevated potassium (K+) values in their patients. Bloods for K+ and chemistry profiles are routinely collected in mint-green, heparinized plasma separator tubes (PST), centrifuged, and transported by courier from satellite clinic to CCL within several hours. Samples from on-site phlebotomy areas are similarly collected but sent uncentrifuged to CCL via a pneumatic tube system within minutes of collection. Methods Our investigations included extensive QC and QA review of UCMC onsite and offsite outpatient clinics, reference range studies using PST and serum separator tubes (SST), assessment of pre-analytic handling of specimens, including transportation simulation study, and comparison of K+ results for samples collected simultaneously using PST and SST tubes at an offsite clinic. Results Our transportation simulation demonstrated elevations in K+ concentrations following sample jostling and perturbations. We also observed RBC escape across the gel barrier further contributing to K+ elevations. Conclusion Serum is preferred sample type for an offsite clinic.

Background We performed a 3-way comparison on the Osmetech eSensor®, AutoGenomics INFINITI™, and a real-time PCR method (Paragonx™ reagents/Stratagene® RT-PCR platform) for their FDA-cleared warfarin panels, and additional polymorphisms (CYP2C9 ⁎5, ⁎6, and ⁎11 and extended VKORC1 panels) where available. Methods One hundred de-identified DNA samples were used in this IRB-approved study. Accuracy was determined by comparison of genotyping results across three platforms. Any discrepancy was resolved by bi-directional sequencing. The CYP4F2 on Osmetech was validated by bi-directional sequencing. Results Accuracies for CYP2C9 ⁎2 and ⁎3 were 100% for all 3 platforms. VKORC1 3673 genotyping accuracies were 100% on eSensor and 97% on Infiniti. CYP2C9 ⁎5, ⁎6 and ⁎11 showed 100% concordance between eSensor and Infiniti. VKORC1 6484 and 9041 variants compared between ParagonDx and Infiniti analyzer were 100% (6484) and 99% (9041) concordant. CYP4F2 was 100% concordant with sequencing results. The time required to generate the results from automated DNA extraction-to-result was approximately 8 h on Infiniti, and 4 h on eSensor and ParagonDx, respectively. Conclusions Overall, we observed excellent CYP2C9 ⁎2 and ⁎3 genotyping accuracy for all three platforms. For VKORC1 3673 genotyping, eSensor demonstrated a slightly higher accuracy than the Infiniti, and CYP4F2 on Osmetech was 100% accurate.

Pharmacogenomics promises to improve therapeutic care by providing the right drug and dosage to the appropriate patient. Despite widespread interest in personalized medicine, the implementation of clinical pharmacogenomics has been slow. The major issue for clinicians is the lack of evidence that pharmacogenomic testing improves clinical outcomes and that testing is cost-effective. Only a few randomized clinical trials comparing pharmacogenomic testing with standard protocols have been conducted. The few studies that are available have either been underpowered or demonstrated only modest benefits. Nevertheless, if clinical decisions are made regarding therapeutic selection and dosing, pharmacogenomic testing may be justified. Issues for the clinical laboratories (who are responsible for providing pharmacogenomic services) to consider, include the availability of US FDA-cleared tests, the absence of reimbursement codes, the need for genotyping accuracy and the need to find clinical expertise to interpret laboratory results. From the clinical laboratory perspective, testing can be better implemented when these barriers are resolved or minimized. Clinical pharmacogenomics also offers a new field for translational research and teaching at various levels.

Background : Brain natriuretic peptides (BNPs) are useful in the assessment of heart failure, left ventricular dysfunction, and acute coronary syndromes. Methods : We performed a multicenter evaluation of the automated Roche NT-proBNP assay and compared its performance to the Biosite Triage BNP assay. Results : The N-terminal (1–76) pro brain natriuretic peptide (NT-proBNP) method is precise (CV≤6.1%), has a wide dynamic measuring range (30–35,000 ng/l), is free from common interferences, and does not cross-react with BNP. EDTA or heparinized plasma samples collected in glass or plastic tubes can be used, and samples are stable at room temperature or 4 °C for up to 3 days. In contrast, the Biosite BNP assay has >2-fold higher CV, and plasma samples are more labile when stored at room temperature and 4 °C. Comparison studies showed a reasonable correlation between NT-proBNP and BNP assays, with a substantially higher slope bias of 6–20 for the NT-proBNP assay. Conclusions : The automated Roche NT-proBNP assay has good analytical performance and better precision than the Biosite BNP assay. Unlike BNP, NT-proBNP is stable in EDTA plasma for 3 days at room temperature or longer at 4 °C. The Roche NT-proBNP is fully automated and will accommodate the testing of large numbers of clinical samples for assessing cardiac dysfunction.

Background Although patients with medullary thyroid cancer are known to present with paraneoplastic hormone production, this is much less common with papillary thyroid cancer. Methods We present a patient with the cribriform morular variant of papillary thyroid cancer in association with familial adenomatous polyposis who developed a positive pregnancy test in the absence of known pregnancy. The patient had developed vaginal bleeding, and her laboratory testing was characterized by elevated serum human chorionic gonadotropin (β-hCG) concentrations, but negative qualitative urine results. After a thorough gynecological evaluation to exclude unexpected normal, ectopic, or molar pregnancy, we pursued an evaluation for other sources of β-hCG production. Results We showed that the elevated serum β-hCG concentrations were not the result of heterophile antibody interferences, and ultimately we proved that her recurrent tumor produced the ectopic β-hCG. This is the first report of β-hCG production by papillary thyroid cancer. Thus, the possibility of ectopic production of β-hCG by papillary thyroid cancer needs to be included in the differential diagnosis of elevated hCG concentration in the absence of pregnancy. Conclusions This study of an unusual paraneoplastic syndrome highlights the importance of investigating discrepancies in the clinical laboratory.

The presence of heterophilic antibodies in the serum of a small subpopulation of individuals continues to cause false results for modern-day immunoassays. In order to determine the frequency of heterophilic antibody (HA)-related false positives within our population of positive cardiac troponin I (cTnI) patients, we assayed 200 samples using the original in-house cTnI assay (Abbott AxSYM) and the Bayer ACS:180 cTnI, which we had previously observed to be more effective at blocking HA interference. Four samples were identified as false positives based on discordant results between the two assays, as well as the correction of the false positives by treatment of the samples with heterophilic antibody blocking reagent (HBR). An 'enhanced' version of the AxSYM cTnI reagent was designed to greatly reduce or eliminate HA interference, and has now replaced the original reagents. The present study shows that the enhanced reagent significantly reduced or eliminated much of the HA interference. Comparative studies between the enhanced cTnI reagent and the original Abbott AxSYM cTnI reagent showed excellent correlation and equivalent diagnostic concordance, when HA samples were excluded from the analysis.

Elevated vascular endothelial growth factor (VEGF) levels are required for ocular and tumor angiogenesis in animal models. Ischemic hypoxia is strongly correlated with increased VEGF expression in these systems and is considered a physiologically relevant stimulus. Because ischemic hypoxia is often followed by reperfusion and reactive oxygen intermediate (ROI) generation, we examined the potential role of ROI in the control of VEGF gene expression. Human retinal pigment epithelial cells exposed to superoxide or hydrogen peroxide rapidly increased VEGF mRNA levels. Superoxide-associated mRNA increases were dose dependent, blocked by antioxidants, and associated with elevated VEGF protein levels in conditioned media. Increases in VEGF mRNA levels were also observed in cultured human melanoma and rat glioblastoma cells with superoxide or hydrogen peroxide. Cycloheximide prevented the ROI-associated increases in VEGF mRNA. Transcriptional inhibition with actinomycin D revealed an inducible increase in VEGF mRNA half-life, but nuclear run-on experiments showed no increase in VEGF transcriptional rate. Reoxygenation of human retinal pigment epithelial cells in vitro and ocular reperfusion in vivo increased retinal VEGF mRNA levels. Antioxidants prevented the reperfusion-associated VEGF mRNA increases in retina. We conclude that ROIs increase VEGF gene expression in vitro and during the reperfusion of ischemic retina in vivo. The ROI-associated increases are mediated largely through increases in VEGF mRNA stability.

Background CYP2C19 variants have been demonstrated to play an important role in determining response to clopidogrel and outcomes while on clopidogrel therapy. Predicting patient response through pre-therapeutic genotyping may therefore guide selection of antiplatelet therapy. Methods CYP2C19 genotypes were determined for 111 samples with the eSensor and compared with the Autogenomics expanded CYP2C19 panel, Luminex reagents, and bi-directional sequencing. Samples were obtained from the University of Chicago, ARUP Laboratories, and the Coriell repositories. Reproducibility studies were performed with 5 DNA samples with known CYP2C19 genotypes. Results Complete concordance was observed for all samples and all platforms. DNA concentrations as low as 0.05 ng/μl may be used on the eSensor platform. There was 100% reproducibility observed with 2.5% incidence of invalid tests. Conclusions The eSensor CYP2C19 genotyping assay is accurate and compares well with 2 current commercial platforms. With a relatively rapid turn-around time of ~ 4 h and a high rate (97.5%) of valid tests, the eSensor can be translated into clinical use to identify slow and rapid metabolizers of clopidogrel who may benefit from alternate therapy or unconventional dosing of clopidogrel. An observed limitation of the eSensor is a maximum capacity of 24 tests/run.

Objective: Assessment of platelet function testing is often limited when platelet counts are low, as typically found in pediatric and thrombocytopenic populations. We aim to develop a high sensitive method for measuring the release of endogenous serotonin by mass spectrometry to address this limitation. Methods: 100 μL citrated blood was diluted 10-fold to 1.0 mL with Modified HEPES/Tyrode Buffer (MTB). 80 μL of the diluted blood was then incubated with a platelet agonist, such as ADP, unstirred, …

Introduction Oxycodone has become widely used in the clinic for the treatment of chronic pain. This reflects its favorable pharmacokinetics and side effect profiles. Case report We report a 60-y-old man who had a clinically significant drug interaction between rifampin and oxycodone, resulting in 3 consecutive negative urine oxycodone screens in a 2-month period, suggesting non-adherence. A combination of urine opioid metabolite quantification by GC/MS and CYP genotyping confirmed that he was compliant with his oxycodone therapy. Determination of the complete oxycodone metabolite profile and the CYP3A4/5 and 2D6 genotype allowed the physician to be confident that the patient was compliant with the medication (and not diverting it) and to increase his oxycodone dose to optimize his pain control. Conclusion This case demonstrates how the combination of analytical toxicology and pharmacogenetic analyses enhances a physician's ability to personalize drug therapy in patients with chronic pain syndromes.

Objective To determine whether serum levels of vascular permeability factor (VPF) are elevated in patients with ovarian hyperstimulation syndrome (OHSS) and to determine if luteinizing granulosa cells may be a source of VPF. Design Prospective observational study. Setting University IVF and GIFT program. Patients Eight consecutive IVF and GIFT patients at high risk for OHSS. Main Outcome Measures Vascular permeability factor concentration in serum and follicular fluid. Results Serum VPF was significantly higher (15.2 ± 4.0 pM; mean ± SEM) on day +14 in the group who developed severe OHSS compared with those who did not. Follicular fluid VPF (171.5 ± 18.5 pM) was approximately 100-fold greater than serum (1.7 ± 1.3 pM) or peritoneal fluid (2.5 ± 1.3 pM) 36 hours after hCG administration. Conclusion Vascular permeability factor is elevated in patients with severe OHSS and the ovary may be a source of VPF secretion.

Citrate anticoagulation has been used as an alternative to heparin for hemodialysis in high-risk patients; however, its use in hemofiltration has not been well studied. We examined citrate in 6 patients placed on slow hemofiltration for up to 6 h duration. During the experiments, the systemic citrate level increased from a baseline average of 0.15 to 0.55 mmol/l, and then decreased to 0.27 mmol/l. The citrate was freely filtered. The systemic total and ionized calcium decreased very slightly and no untoward effects were noted. Anticoagulation was successful. This preliminary study suggests that citrate anticoagulation can be used in slow hemofiltration.

Atrial natriuretic factor (ANF) is a peptide released from the heart in response to atrial distension. This peptide causes diuresis, vasodilatation, decreased blood pressure, and antagonizes the renin-aldosterone and antidiuretic hormone neuraxes. The influence of cardiopulmonary bypass and cardiac surgery on the circulation and release of ANF is unknown. Plasma ANF concentrations were therefore determined in patients undergoing coronary artery revascularization (CABG) and mitral valve replacement (MVR). Peptide levels were unchanged following anaesthetic induction. Plasma ANF concentrations decreased significantly during hypothermic (less than or equal to 28 degrees C) cardiopulmonary bypass in both patient groups. After 60 minutes of cardiac bypass, ANF declined from (mean +/- SEM) 512 +/- 132 to 20 +/- 6 pg.ml-1 (P less than 0.05) during MVR, and from 178 +/- 41 to 110 +/- 48 pg.ml-1 during CABG (P less than 0.05). Rewarming during bypass was associated with an increase in ANF concentration in both groups. Heparin anticoagulation and protamine reversal had no effect on immunoreactive ANF levels. In patients undergoing CABG, there was a linear relationship between plasma ANF concentration (pg.ml-1) and right atrial pressure (mmHg) prior to cardiopulmonary bypass (r = 0.86, P less than 0.005). However, one and three hours after cardiopulmonary bypass there was no significant relationship between right atrial pressure and ANF plasma levels. These results suggest that reduction in plasma ANF concentration occurs during hypothermic cardiopulmonary bypass. Furthermore, the proportional relationship between atrial distension and circulating ANF concentration was altered following cardiac surgery.