Diagnostic performance of specific biomarkers for interstitial lung disease: a single center study.

Objectives: This study aimed to determine the clinical significance of Krebs von den Lungen-6 (KL-6), surfactant proteins A (SP-A) and D (SP-D) in the evaluation and management of interstitial lung disease (ILD).

Methods: Serum KL-6, SP-A, SP-D levels were measured in 122 unique consecutive patients referred for connective tissue disease (CTD) associated ILD (CTD-ILD) autoantibodies and 120 "healthy" controls. Patients' charts were retrospectively reviewed and categorized as ILD and non-ILD or CTD-ILD and other ILD.

Evaluation of an adenosine deaminase (ADA) assay in serum, pleural, pericardial, peritoneal, and cerebrospinal fluids on the Roche cobas c501 analyzer.

Objectives: Adenosine deaminase (ADA) can be increased in various body fluids during infectious and inflammatory states. The objective of this study was to evaluate the performance characteristics of the Diazyme ADA assay for serum, pleural, pericardial, peritoneal, and cerebrospinal fluids using the Roche cobas c501 analyzer.

Methods: Accuracy, linearity, recovery, precision, sensitivity, specificity, reference interval, and stability studies were conducted.

Mitigation of Biotin Interference in Manual and Automated Immunoassays by Preconjugating Biotinylated Antibodies to the Streptavidin Surface as an Alternative to Biotin Depletion.

Background: Streptavidin-to-biotin binding is one of the strongest noncovalent interactions in nature and incorporated into many immunoassays. Biotin-streptavidin coupling assays are susceptible to interference from free biotin in patient specimens, which may falsely decrease or increase results. To prevent biotin interference, we evaluated a method to preconjugate biotinylated antibodies to the assay's streptavidin solid surface before adding patient specimen and compared this technique to a biotin depletion protocol.

Tobacco and Cannabis Use During Pregnancy.

Objectives: Nicotine (NIC) use during pregnancy can influence markers used in biochemical maternal serum screening. This study was designed to determine prevalence of disclosed tobacco smokers in our patient population and to compare disclosed tobacco smoking status with the presence of serum nicotine and a common tetrahydrocannabinol (THC) metabolite.

Methods: A deidentified dataset of disclosed smoking status for quadruple (Quad) screens was obtained.

Excessively low cholesterol and triglyceride levels in an apparently healthy patient.

Lipid panels are a commonly performed test in clinical laboratories. Due to the high prevalence of cardiovascular diseases around the world, it is common to see serum or plasma specimens with high results for one or more components of the lipid panel. Exceedingly low results, however, are rare and may be attributed to certain genetic, infectious, or autoimmune conditions in addition to analytical interference.

Pretreatment of Body Fluid Specimens Using Hyaluronidase and Ultracentrifugation.

Objective: Viscous body fluids present challenges during clinical laboratory testing. The present study was conducted to evaluate the effectiveness of hyaluronidase (HYAL) and ultracentrifugation (UC) pretreatment for a variety of body fluids before clinical chemistry testing.

Methods: The following body fluids were evaluated: biliary/hepatic, cerebrospinal, dialysate, drain, pancreatic, pericardial, peritoneal/ascites, pleural, synovial, and vitreous.

Plasma hemoglobin: A method comparison of six assays for hemoglobin and hemolysis index measurement.

Introduction: Plasma hemoglobin (Hb) is measured for assessment of in vivo and in vitro hemolysis. The objective of the present investigation was to conduct a method comparison of five quantitative and one semi-quantitative Hb and H-index (hemolysis index) assays to evaluate their performance measuring plasma Hb in clinical specimens.

Methods: One hundred and fourteen clinical specimens previously tested for plasma Hb using a laboratory-developed spectrophotometric assay were also tested for Hb using a HemoCue Plasma/Low Hb assay (azide methemoglobin), a laboratory-modified Pointe Scientific Hb assay (cyanmethemoglobin), tested for H-index measurements using a Roche cobas c501, an Abbott Architect c8000, and a semi-quantitative (binned) H-index measurement on a Beckman AU5800.

Evaluation of 3 SARS-CoV-2 IgG Antibody Assays and Correlation with Neutralizing Antibodies.

Background: As serologic assays for SARS-CoV-2 become more widely utilized, it is important to understand their performance characteristics and correlation with neutralizing antibodies. We evaluated 3 commonly used SARS-CoV-2 IgG assays (Abbott, DiaSorin, and EUROIMMUN) for clinical sensitivity, specificity, and correlation with neutralizing antibodies, and then compared antibody kinetics during the acute phase of infection.

Methods: Three panels of samples were tested on every assay.

Laboratory evaluation of homocysteine remethylation disorders and classic homocystinuria: Long-term follow-up using a cohort of 123 patients.

The homocystinurias, caused by defects of remethylation and cystathionine-beta-synthase (CBS) deficiency, are characterized by elevated homocysteine and abnormal methionine levels. Various treatments, including injectable hydroxycobalamin and oral betaine, aim to reduce homocysteine toxicity and normalize methionine, but only limited biochemical data has been reported assessing biochemical response to treatment. We analyzed laboratory results in 812 plasma samples from 56 patients with remethylation disorders and 67 patients with CBS deficiency.

Identifying and Eliminating Laboratory Contamination by Topical Testosterone Therapeutics.

Many prescription and over-the-counter drugs are available as topical formulations. Contamination of clinical laboratory workspaces by topical drugs may increase the risk of potential interference with diagnostic testing. An example of localized workspace contamination attributed to a topical hormonal drug (testosterone, T) is presented to highlight significant challenges in identifying and resolving this potential problem.

Antibodies to small ubiquitin-like modifier activating enzyme are associated with a diagnosis of dermatomyositis: results from an unselected cohort.

The aim of this study was to examine the frequency and significance of antibodies targeting the small ubiquitin-like modifier 1 activating enzyme (SAE) in patients under serologic evaluation for idiopathic inflammatory myopathies. Patient sera (n = 17) recognizing bands at approximately 40 (SAE1) and 90 (SAE2) kDa were identified in 6445 consecutive samples for myositis autoantibody evaluation by immunoprecipitation (IP) of S-labeled K562 cell lysate. All 17 positive samples, 176 disease, and 67 healthy controls were evaluated for SAE1 antibodies using a line immunoblot assay (LIA).

How low can you go? Analytical performance of five automated testosterone immunoassays.

Background: Testosterone is commonly measured using immunoassays, yet concerns with the accuracy and quality of testing by these methods exist, particularly for low testosterone concentrations. Study objectives were to evaluate selective performance characteristics, including functional sensitivity (FS), of 5 automated immunoassays for total testosterone.

Methods: FS, imprecision, assay interference, limit of blank, linearity, and accuracy were assessed using the Abbott ARCHITECT i2000, SIEMENS ADVIA Centaur and IMMULITE 2000, Beckman Coulter DxI 800, and Roche MODULAR E170.

Lipemic interference of ceruloplasmin assays - An evaluation of lipid removal methods.

Background: The present studies were conducted to characterize lipemic interference across three FDA-cleared ceruloplasmin (CERU) assays and to evaluate procedures designed to remove lipemic interference.

Methods: CERU assays on the Abbott ARCHITECT ci8200, Beckman AU5800, and Roche cobas Integra 400 Plus were evaluated. Precision, linearity with dilution, lipemic interference, and three methods for removing lipemia were assessed on each platform: ultracentrifugation (UC), lipemia-clearing reagent LipoClear (LC), and 1:5 dilution (DIL).

Detection of autoantibodies to 3-hydroxy-3-methylglutaryl-coenzyme a reductase by ELISA in a reference laboratory setting.

Background: We investigated the performance of an ELISA for the detection of 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase (HMGCR) IgG antibodies in immune-mediated necrotizing myopathies (IMNM).

Methods: Patients positive for HMGCR antibodies (n=61) or negative (n=78) by protein immunoprecipitation (IP), and healthy controls (n=100) were used to evaluate the ELISA. Unique consecutive serum samples (n=155) received at ARUP Laboratories for HMGCR IgG testing by ELISA were also investigated and analysed for serum muscle enzymes (aldolase, creatine kinase, and myoglobin).

Comparative analysis of neutrophil gelatinase-associated lipocalin and other laboratory markers for lupus nephritis: a cross-sectional investigation.

Background Lupus nephritis is one of the most serious complications of systemic lupus erythematosus. This study evaluates the prevalence and correlation between neutrophil gelatinase-associated lipocalin and other biomarkers associated with renal involvement in systemic lupus erythematosus. Methods Paired serum and urine specimens from 50 suspected systemic lupus erythematosus patients, characterized by antinuclear antibodies detected by indirect immunofluorescence assay and varying positive concentrations of anti-double stranded DNA antibodies by Crithidia luciliae immunofluorescence assay, were investigated.

Pediatric Reference Intervals for Free Thyroxine and Free Triiodothyronine by Equilibrium Dialysis-Liquid Chromatography-Tandem Mass Spectrometry.

Objective: Thyroid hormone concentrations fluctuate during growth and development. To accurately diagnose thyroid disease in pediatric patients, reference intervals (RIs) should be established with appropriate age groups from an adequate number of healthy subjects using the most exact methods possible. Obtaining statistically useful numbers of healthy patients is particularly challenging for pediatric populations.

Ordering of the Serum Angiotensin-Converting Enzyme Test in Patients Receiving Angiotensin-Converting Enzyme Inhibitor Therapy: An Avoidable but Common Error.

Background: Serum angiotensin-converting enzyme (ACE) levels may be decreased by use of ACE inhibitor (ACEI) medication. In this study, we determined how often ACE levels were measured in patients receiving ACEI therapy.

Methods: ACE levels analyzed over a 54-month preintervention time period at an academic medical center were reviewed retrospectively for tests performed during ACEI therapy.

Evaluation of test strips for the rapid identification of ethylenediaminetetraacetic acid (EDTA) specimens.

Background: Identification of specimens that contain ethylenediaminetetraacetic acid (EDTA) is frequently necessary when investigating potentially mislabeled or improperly collected specimens.

Objective: To evaluate the performance of rapid EDTA detection test strips in clinical specimens.

Methods: We applied specimens to test strips designed to detect EDTA (QUANTOFIX EDTA) using a pipet (drop mode).

Effects of 49 Different Rare Hb Variants on HbA1c Measurement in Eight Methods.

Background: Previous studies have shown interference with HbA1c measurement from the 4 most common heterozygous Hb variants (HbAS, HbAE, HbAC, and HbAD) with some assay methods. Here we examine analytical interference from 49 different less common variants with 7 different HbA1c methods using various method principles.

Methods: Hb variants were screened using the Bio-Rad Variant or Variant II beta thal short program, confirmed by alkaline and acid electrophoresis, and identified by sequence analysis.

Thrombin-mediated degradation of parathyroid hormone in serum tubes.

Background: Intact parathyroid hormone (PTH) tests are frequently sandwich immunoassays. Enzymes that cleave PTH may cause falsely lower PTH results. The objective of this study was to determine whether bovine thrombin in Becton Dickinson (BD) Vacutainer rapid serum tubes™ (RSTs) may lead to PTH results that are lower than in plasma separator tube™ (PST) or serum separator tube™ (SST) collections.

Multiple macroenzymes in a patient with AIDS: diagnosis using ultrafiltration.

Objectives: Multiple immunoglobulin-bound enzymes (macroenzymes) are reported for the first time in an individual with AIDS. Possible causes and suitable methods of detection are addressed.

Methods: An asymptomatic man with a history of AIDS with hypergammaglobulinemia and elevated creatine kinase, amylase, and liver enzyme concentrations was evaluated before enrollment in a clinical trial.

Performance characteristics of the ARCHITECT Galectin-3 assay.

Objectives: Galectin-3 is an emerging biomarker that is commonly increased in patients with heart failure and/or patients at risk for cardiovascular disease. We evaluated the Galectin-3 assay on the Abbott ARCHITECT i1000(SR) and ARCHITECT i2000(SR) at 2 testing sites.

Design And Methods: Imprecision (%CV), interference, limits of blank (LoB), detection (LoD), and quantitation (LoQ), linearity, method comparison to an ELISA method, comparisons between plasma and serum, and reference intervals were evaluated.