BioBridge Global San Antonio, Texas, United States
Background/Case Studies: The Anti-HBs Immunoassay is essential for quantitating antibodies to hepatitis B surface antigen (HBsAg) in plasma fractionation processes for pooled plasma samples and other applications. The focus was on validating the effectiveness of a commercial immunoassay in quantifying hepatitis B surface antibody levels within pooled plasma sample types. This study aimed to validate the immunoassay's analytical sensitivity, precision, accuracy, linearity, and robustness for use on the Alinity i immunoassay system (Abbott Diagnostics).
Study
Design/Methods: To ensure the reliability and effectiveness of the immunoassay system for Anti-HBs screening, several tests were conducted. Specificity testing involved examining three lots of plasma products with 20 replicates each to calculate mean, standard deviation (SD), and coefficient of variation (%CV). Analytical sensitivity was assessed through probit analysis on samples spiked with WHO anti-HBs standard, calculating mean, SD, %CV, and Limit of Blank (LOB) for each concentration. Precision testing utilized two sets of samples with varying anti-HBs concentrations to determine mean, SD, %CV, and 95% Limit of Detection (LOD). Linearity was evaluated with two sets of samples ranging from 0 to 1000 mIU/mL, calculating mean, SD, %CV, and % recovery for each concentration. Robustness testing involved preparing samples at 3 x 95% probit LOD and testing them in 20 replicates over 2 days. Interference testing included preparing three samples with HBsAg concentrations and testing them in triplicate for Anti-HBs.
Results/Findings: The assay exhibited excellent specificity, as all samples demonstrated nonreactivity. Analytical sensitivity analysis revealed a 95% LOD of 0.51 mIU/mL for both specimen diluent and pooled plasma. Precision and accuracy were maintained within acceptable limits, with %CV values ≤ 30% across all concentrations for within run and intermediate precision. The assay demonstrated outstanding linearity, with correlation coefficients (R2) of 99.99% for specimen diluent and 99.8% for pooled plasma. Linear ranges were determined to be 10 - 1000 mIU/mL with a Limit of Quantitation (LOQ) of 10 mIU/mL for pooled plasma, and 5 -1000 mIU/mL with a LOQ of 5 mIU/mL for specimen diluent. Robustness was confirmed, with all sample replicates testing reactive over two days. In interference studies, the assay consistently detected Anti-HBs up to an HBsAg concentration of 0.150 IU/mL. Conclusions: This study successfully validated the Anti-HBs Immunoassay for use on the Alinity i immunoassay system, affirming its suitability for testing and quantifying hepatitis B surface antibody levels in pooled plasma samples. With excellent analytical sensitivity, precision, accuracy, and linearity, the assay proves valuable for Anti-HBs screening across various applications.
