Diagnostic patterns and stress testing trends after implementing high-sensitivity troponin assay.

Objectives: High-sensitivity troponin T (hsTnT) testing was approved in the United States to better facilitate diagnosis of acute coronary syndrome (ACS). Although hsTnT has been widely studied internationally, the impact of hsTnT on discharge diagnoses and health care utilization within the United States is less known. We sought to evaluate the effects of implementing hsTnT on diagnosis patterns and stress testing utilization.

Reflexing Suspicious β-Region Findings on Capillary Serum Protein Electrophoresis to Immunofixation or Immunosubtraction for Detecting Monoclonal Proteins.

Objectives: Monoclonal immunoglobulins (M-proteins) that migrate in the β region on serum protein electrophoresis (SPEP) are often cloaked by this region's normal constituents. The present study interrogates the utility of using both quantitative and qualitative alterations in β-region bands for detection of β-migrating M-proteins.

Methods: Consecutive SPEP cases analyzed by capillary electrophoresis were searched to identify the initial workup on 1,841 patients with increased total β regions, suspicious β-region findings resulting in reflex immunofixation (IFE), or immunosubtraction (ISUB).

Mild SARS-CoV-2 Illness Is Not Associated with Reinfections and Provides Persistent Spike, Nucleocapsid, and Virus-Neutralizing Antibodies.

Uncertainty exists whether mild COVID-19 confers immunity to reinfection. Questions also remain regarding the persistence of antibodies against SARS-CoV-2 after mild infection. We prospectively followed at-risk individuals with and without SARS-CoV-2 for reinfection and monitored the spike and nucleocapsid antibodies.

Differences in Performance Characteristics Among Four High-Throughput Assays for the Detection of Antibodies Against SARS-CoV-2 Using a Common Set of Patient Samples.

Objectives: Serologic testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has experienced a changing landscape of available assays coupled with uncertainty surrounding performance characteristics. Studies are needed to directly compare multiple commercially available assays.

Methods: Residual serum samples were identified based on SARS-CoV-2 reverse transcription polymerase chain reaction (RT-PCR) testing, clinical test results, and collection dates.

Comprehensive Analysis of Steroid Biomarkers for Guiding Primary Aldosteronism Subtyping.

Adrenal vein sampling (AVS) is required to distinguish unilateral from bilateral aldosterone sources in primary aldosteronism (PA), and cortisol is used for AVS data interpretation, but cortisol has several pitfalls. In this study, we present the utility of several other steroids in PA subtyping, both during AVS, as well as in peripheral serum. We included patients with PA who underwent AVS at University of Michigan between 2012 and 2018.

Interpretation of common endocrine laboratory tests: technical pitfalls, their mechanisms and practical considerations.

Pitfalls in hormonal assays are commonly seen in clinical practice and may lead to erroneous clinical impressions and treatments. In this article, we address common laboratory pitfalls encountered during evaluation of patients with real or presumed endocrine disorders including high dose hook effect and falsely normal prolactin in cases of macroprolactinomas, macroprolactinemia and falsely elevated prolactin, macrothyrotropinemia and falsely elevated TSH, heterophile antibodies leading to false elevation of hormonal concentration, biotin interference with different hormonal assays, cross-reactivity of steroid hormones immunoassays, and others. We describe the mechanisms of such laboratory pitfalls, review clinical scenarios in which they might occur, and discuss the ways to resolve such conundrums.

Effect of Diabetes Mellitus on Sickle Hemoglobin Quantitation in Sickle Cell Trait.

Objectives: We evaluated the effect of diabetes on sickle hemoglobin (HbS) measurement on two common clinical hemoglobin separation platforms.

Methods: We performed a method comparison between the Bio-Rad Variant II high-performance liquid chromatography (HPLC) and Sebia Capillarys 2 Flex Piercing capillary electrophoresis (CE) using clinical specimens from 38 patients without hemoglobin variants and 57 patients with sickle cell trait (AS) (HbA1c%, 4.1%-15.

Quality Control Practices for Chemistry and Immunochemistry in a Cohort of 21 Large Academic Medical Centers.

Objectives: In the United States, minimum standards for quality control (QC) are specified in federal law under the Clinical Laboratory Improvement Amendment and its revisions. Beyond meeting this required standard, laboratories have flexibility to determine their overall QC program.

Methods: We surveyed chemistry and immunochemistry QC procedures at 21 clinical laboratories within leading academic medical centers to assess if standardized QC practices exist for chemistry and immunochemistry testing.

Doxorubicin-induced cardiac dysfunction in unselected patients with a history of early-stage breast cancer.

Cardiomyopathy is a known complication of anthracycline-based adjuvant chemotherapy and is more commonly reported in population-based studies of breast cancer survivors than in clinical trials. This study prospectively evaluated the prevalence of elevated cardiac biomarkers in unselected patients who had been treated with doxorubicin for early-stage breast cancer and the prevalence of reduced LVEF in patients with an elevated biomarker. All participants underwent an examination, symptom inventory, medical record review, and biomarker analysis for BNP, troponin, and plasma and urine NT-proBNP.

Lipoprotein (a): perspectives from a lipid-referral program.

Background: Lipoprotein (a) [Lp(a)] has a strong association with coronary disease (CHD). We evaluated the implications of implementing a niacin strategy in persons above low risk by the Framingham risk score (FRS).

Methods: Patients referred to a university lipid management program from January 2004 to June 2010 had an Lp(a) level measured at initial evaluation.

Forced TR2/TR4 expression in sickle cell disease mice confers enhanced fetal hemoglobin synthesis and alleviated disease phenotypes.

Sickle cell disease (SCD) is a hematologic disorder caused by a missense mutation in the adult β-globin gene. Higher fetal hemoglobin (HbF) levels in red blood cells of SCD patients have been shown to improve morbidity and mortality. We previously found that nuclear receptors TR2 and TR4 repress expression of the human embryonic ε-globin and fetal γ-globin genes in definitive erythroid cells.

Autoantibody profiles reveal ubiquilin 1 as a humoral immune response target in lung adenocarcinoma.

There is considerable evidence that the presence of cancer can elicit a humoral immune response to specific proteins in the host, and these resulting autoantibodies may have potential as noninvasive biomarkers. To characterize the autoantibody repertoire present in the sera of patients with lung adenocarcinoma, we developed a high-density peptide microarray derived from biopanning a lung cancer phage display library. Using a 2,304-element microarray, we interrogated a total of 250 sera from Michigan lung cancer patients and noncancer controls to develop an "autoantibody profile" of lung adenocarcinoma.

Autoantibody signatures in prostate cancer.

Background: New biomarkers, such as autoantibody signatures, may improve the early detection of prostate cancer.

Methods: With a phage-display library derived from prostate-cancer tissue, we developed and used phage protein microarrays to analyze serum samples from 119 patients with prostate cancer and 138 controls, with the samples equally divided into training and validation sets. A phage-peptide detector that was constructed from the training set was evaluated on an independent validation set of 128 serum samples (60 from patients with prostate cancer and 68 from controls).

Use of B-natriuretic peptide as a diagnostic marker in the differential diagnosis of transfusion-associated circulatory overload.

Background: Transfusion-associated circulatory overload (TACO) occurs when the transfusion rate or volume exceeds the capacity of a compromised cardiovascular system. Characteristic symptoms and signs associated with TACO are neither sensitive nor specific. B-natriuretic peptide (BNP) is a 32-amino-acid polypeptide secreted from the cardiac ventricles in response to ventricular volume expansion and pressure overload.

Humoral immune response to alpha-methylacyl-CoA racemase and prostate cancer.

Background: Although prostate-specific antigen (PSA) is a prototypic biomarker for prostate cancer, it has poor specificity. Expression of alpha-methylacyl-CoA racemase (AMACR), which is involved in the conversion of R-stereoisomers of branched-chain fatty acids to S-stereoisomers, has been shown to be specifically increased in prostate cancer epithelia. However, attempts to detect AMACR in circulation have not been successful.

Analytical and clinical validation of a radioimmunoassay for the measurement of 1,25 dihydroxy vitamin D.

Objectives: The analytical and clinical validation of the DiaSorin 1,25 dihydroxyvitamin D RIA is described.

Design And Methods: The analytical parameters assessed included analytical sensitivity, dilution linearity, intra- and inter-assay precision, recovery, specificity, and interference studies. Where appropriate, assessments were performed according to NCCLS guidelines.

Cardiovascular risk factors in ethnic minority women aged < or =30 years.

Men and women of African and South Asian ancestry in the United States are increasingly recognized as being at greater risk for coronary heart disease (CHD) than Caucasians of European ancestry. Relatively little data on the genetic and lifestyle risk factors that predispose women to CHD in these ethnic minorities are available. We compared coronary risk factors in a volunteer sample of African-American, Asian Indian American, and Caucasian American women of college age.