A-319 Evaluation of Hepatitis C Antibody Results by Immunoassay and Polymerase Chain Reaction Methods

Abstract Background Any reactive hepatitis C Virus Antibody (HCV Ab) test requires confirmation by PCR method. This testing procedure requires submission of two separate sample tubes–one serum, the other plasma. The serum tube is tested for HCV antibody and if Reactive, the plasma tube is tested for HCV RNA by a quantitative Polymerase Chain Reaction (PCR) method. The false positive rate among many immunoassay methods is high and this lead to unnecessarily PCR measurements. Therefore, this procedure may not be cost effective and delaying the diagnosis and treatment. The aim of this study was to analyze our last year data in order to draw a baseline to improve our laboratory services and to support hepatitis C diagnosis among our community by evaluating the immunoassay and PCR results for HCV infection. Methods We have retrospectively reviewed the lab results for HCV Ab and the confirmatory PCR through the electronic hospital system during the year 2024. The PCR technique has performed for any reactive or borderline HCV Ab. The HCV Ab samples have measured by Chemiluminescence immunoassay (CLIA) Alinity (Abbott). The PCR measurements were performed by Alinity (Abbott) analyzer. Any result above the cutoff 1.1 units was considered reactive. Any results between 0.9 and 1.1 have considered a borderline. This study has conducted in Riyadh, Saudi Arabia. Results Total of 78228 HCV Ab results was reviewed. Almost 76,920 (98.3%) were nonreactive for HCV Ab and no further testing was performed. The number of samples with borderline results have found to be 444 (0.57%) with all confirmed non-detected by PCR. For those with reactive HCV Ab have shown to be 864 (1.10%) with 64 (0.74%) which is representing around 0.08% incidence of positive hepatitis C infection among studied population. The false positive rate has found to be 1.03% Conclusion The false positive rate was low and acceptable in this population by Chemiluminescence immunoassay (CLIA) Alinity (Abbott). Increasing of cutoff value may be of benefit to reduce the false positive rate further.