Precision and diagnostic accuracy verification of VITROS HIV combo assay

Abstract

Background/Objective: NACO has laid down three structured algorithms (I, II, III) for HIV screen, surveillance and diagnosis. It is the responsibility of the laboratories to select, verify and evaluate the methods fitting into the algorithm of HIV testing. The present study has attempted to evaluate VITROS® HIV combo assay through comparison with Abbott Architect HIV combo assay. Method: The study evaluated VITROS® HIV combo assay through precision verification and diagnostic accuracy assessment by adopting CLSI guidelines. Precision verification of the VITROS HIV combo assay is done based on CLSI EP15A3 and diagnostic accuracy verification based on CLSI EP12A2. Result: Precision verification showed a repeatability CV% (CVR) -2.35% and within lab CV% (CVWL)-3.77%. This was compared against the manufacturer’s claims (σR-3%, σWL-4.8%) and found to be within acceptable limits. Diagnostic accuracy verification showed that difference in paired sensitivity between VITROS® HIV combo assay and Abbott Architect HIV combo assay was zero and difference in paired specificities was 0.3%. This difference was proved to be statistically insignificant based on 95% confidence interval for the paired sensitivities and specificities. Conclusion: The study showed an acceptable performance of VITROS HIV combo assay in terms of precision and diagnostic accuracy.