Comparison of a dual antibody and antigen HCV immunoassay to standard of care algorithmic testing.

The Centers for Disease Control and Prevention (CDC) guidelines for hepatitis C virus (HCV) testing, although effective, may miss crucial diagnostic opportunities. The goal of this study was to assess the utility of an antibody (Ab) and antigen (Ag) combination immunoassay as an alternative to traditional HCV screening. Remnant specimens from 1,341 patients with concurrent third-generation serologic (Roche anti-HCV-II) and nucleic acid amplification testing (NAAT) were assessed using the HCV Duo Ab/Ag immunoassay (Roche). Patient demographics, risk factors, and standard of care (SOC) laboratory results from the medical records were recorded. Overall, 99.0% (197/199) of the HCV Duo Ab+/Ag+specimens accurately identified active infections as confirmed by NAAT, and 99.9% (670/671) Ab-/Ag- samples corresponded to those without HCV infections. Individually, the HCV Duo Ab component demonstrated a 95.6% positive percent agreement (PPA) (95% CI = 93.8-96.9) and 99.1% negative percent agreement (NPA) (98.8-99.6) compared with SOC anti-HCV II Ab assay. The HCV Duo Ag had a 73.5% PPA (67.9-78.4) and 99.8% NPA (99.3-100) with NAAT. Among RNA+ specimens, 73.4% (197/267) were HCV Duo Ag+, and 265/267 (99.3%) were successfully detected on the HCV Duo Ab component. Notably, 5/7 (71.4%) Ab-/RNA +specimens were detected by HCV Duo, which would have been missed by traditional algorithmic testing. Fourth generation HCV Duo Ab/Ag assay demonstrated comparable performance to SOC testing and shortens the diagnostic window but does not eliminate the need for NAAT in all patients. Ab/Ag testing identified several Ab-/RNA+ cases, a subgroup often undiagnosed by current algorithmic testing, demonstrating promise for improved diagnostic efficiency and accuracy in HCV detection.IMPORTANCEThis study highlights the potential of a combined hepatitis C virus (HCV) Duo antibody (Ab) and antigen (Ag) immunoassay to improve early detection of HCV infections. Traditional Ab-only screening methods recommended by the Centers for Disease Control and Prevention may miss early-stage infections. The HCV Duo assay showed high accuracy, detecting nearly all active infections confirmed by nucleic acid amplification testing. Dual detection of HCV Ab and Ag shortens the diagnostic window, enabling intervention and treatment in a single visit, which is crucial for improving patient outcomes and reducing HCV transmission, especially in areas with limited access to confirmatory molecular testing.

Clinical specificity of two assays for immunoglobulin kappa and lambda free light chains.

OBJECTIVES: Free light chain (FLC) assays and the ratio of κ/λ are recommended for diagnosis, prognosis and monitoring of plasma cell dyscrasias (PCD). Limited data exists on FLC clinical specificity in patients diagnosed with other conditions. METHODS: We assessed the κ, λ, and κ/λ FLC ratio using the FreeLite assay and the Sebia FLC ELISA assay in 176 patients with clinical presentations of fatigue, anemia, polyclonal hypergammaglobulinemia, joint disorders, kidney disease and non PCD-cancers with no monoclonal protein observed on serum protein electrophoresis or MASS-FIX immunoglobulin isotyping. Manufacturer defined reference intervals (RI) and glomerular filtration rate (GFR) specific RI (renal RI) were utilized. RESULTS: For the κ/λ ratio, 68.7 % (121/176) of specimens on the FreeLite and 87.5 % (154/176) of specimens on the Sebia assay were within RI. For κ, 68.2 % (120/176) and 72.2 % (127/176) of results were outside RI for FreeLite and Sebia respectively. For λ, 37.5 % (66/176) and 84.1 % (148/176) of FreeLite and Sebia results were outside RI. With FreeLite and Sebia, patients with kidney disease (n=25) had the highest κ/λ ratios. 44 patients (25.0 %) had GFR <60 mL/min/BSA. When renal RI were applied, 13.6 % had a FLCr outside the renal RI with FreeLite, and 4.5 % with Sebia. CONCLUSIONS: In a cohort of patients with signs and symptoms suggestive of PCDs, but ultimately diagnosed with other conditions, Sebia FLC had improved clinical specificity relative to FreeLite, if one was using an abnormal κ/λ ratio as a surrogate for monoclonality.

Cardiac Troponin to Adjudicate Subclinical Heart Failure in Diabetic Patients and a Murine Model of Metabolic Syndrome.

BACKGROUND: Cardiovascular disease, kidney health, and metabolic disease (CKM) syndrome is associated with significant morbidity and mortality, particularly from congestive heart failure (CHF). Guidelines recommend measurement of cardiac troponin (cTn) to identify subclinical heart failure (HF) in diabetics/CKM. However, appropriate thresholds and the impact from routine screening have not been elucidated. METHODS: cTnI was assessed using the Abbott high sensitivity (hs)-cTnI assay in outpatients with physician-ordered hemoglobin A1c (Hb A1c) and associated with cardiac comorbidities/diagnoses, demographics, and estimated glomerular filtration rate (eGFR). Risk thresholds used in CKM staging guidelines of >10 and >12 ng/L for females and males, respectively, were used. Multivariate logistic regression was applied. hs-cTnI was assessed in a high-fat-diet induced murine model of obesity and diabetes. RESULTS: Of 1304 patients, 8.0% females and 15.7% males had cTnI concentrations above the risk thresholds. Thirty-one (4.2%) females and 23 (4.1%) males had cTnI above the sex-specific 99% upper reference limit. A correlation between hs-cTnI and Hb A1c (R = 0.2) and eGFR (R = -0.5) was observed. hs-cTnI concentrations increased stepwise based on A1C of <5.7% (median = 1.5, IQR:1.3-1.8), 5.7%-6.4% (2.1, 2.0-2.4), 6.5%-8.0% (2.8, 2.5-3.2), and >8% (2.8, 2.2-4.3). Male sex (P < 0.001), eGFR (P < 0.001), and CHF (P = 0.004) predicted elevated hs-cTnI. Obese and diabetic mice had increased hs-cTnI (7.3 ng/L, 4.2-10.4) relative to chow-fed mice (2.6 ng/L, 1.3-3.8). CONCLUSION: A high proportion of outpatients with diabetes meet criteria for subclinical HF using hs-cTnI measurements. Glucose control is independently associated with elevated cTnI, a finding replicated in a murine model of metabolic syndrome.

GPT-4 Underperforms Experts in Detecting IV Fluid Contamination.

BACKGROUND: Specimens contaminated with intravenous (IV) fluids are common in clinical laboratories. Current methods for detecting contamination rely on insensitive and workflow-disrupting delta checks or manual technologist review. Herein, we assessed the utility of large language models for detecting contamination by IV crystalloids and compared its performance to multiple, but variably trained healthcare personnel (HCP). METHODS: Contamination of basic metabolic panels was simulated using 0.9% normal saline (NS), with (n = 30) and without (n = 30) 5% dextrose (D5NS), at mixture ratios of 0.10 and 0.25. A multimodal language model (GPT-4) and a diverse panel of 8 HCP were asked to adjudicate between real and contaminated results. Classification performance, mixture quantification, and confidence was compared by Wilcoxon rank sum. RESULTS: The 95% CIs for accuracy were 0.57-0.71 vs 0.73-0.80 for GPT-4 and HCP, respectively, on the NS set and 0.57-0.57 vs 0.73-0.80 on the D5NS set. HCP overestimated severity of contamination in the 0.10 mixture group (95% CI of estimate error, 0.05-0.20) for both fluids, while GPT-4 markedly overestimated the D5NS mixture at both ratios (0.16-0.33 for NS, 0.11-0.35 for D5NS). There was no correlation between reported confidence and likelihood of a correct classification. CONCLUSIONS: GPT-4 is less accurate than trained HCP for detecting IV fluid contamination of basic metabolic panel results. However, trained individuals were imperfect at identifying contaminated specimens implying the need for novel, automated tools for its detection.