Evaluation of some available HCV antibody detection tests (ELISA, Chemiluminescence, Immune Assay) and RT-PCR assay in the diagnosis of Hepatitis C virus infection

Abstract

Background: The purpose of diagnosis of viral infection is to allow the infected persons to be identified & treated and to prevent blood-transfusion infection. Majority of primary HCV-infected patients are asymptomatic, thus, symptoms could not be used as specific indicators for HCV infection. HCV viremia could still exist despite a normal serum alanine aminotransferase (ALT) level. Therefore, virological methods rather than ALT levels are used to diagnose HCV infection. The diagnosis of HCV infection is mainly based on the detection of anti-HCV antibodies by the enzyme immunoassay(EIA) or Chemiluminescence immunoassay (CIA) of serum samples. These anti-HCV assays are used as a screening test, while PCR is essential for detection of screening test falsity. The presence of HCV-RNA in the serum is a reliable marker of viremia. Universal standardization for HCV-RNA titer is important for diagnosis and follow up. Objective: This study aimed to evaluate the commercially available antibody tests for diagnosis of hepatitis c virus infection in comparison to RT-PCR in Egyptian blood donors. Materials and Methods: This study Included 456 serum samples from blood donor at Al-Hussien hospital blood bank (Al-Azhar University, Cairo) from June 2016 to June 2018. Serum samples subjected to routine laboratory tests (CBC, liver and renal function) to exclude organs affection. Also they are subjected to HCV antibody detection by ELISA and Chemiluminescence tests and HCV–RNA detection by RT-PCR assay. Results: We considered PCR as a standard test to evaluate ELISA and Chemiluminescence. The detected percentage of infectivity of donors in this study was 9% by ELISA, 13% by Chemiluminescence and 8 % by PCR. The percentage of false negativity of HCV antibody by ELISA and CIA when compared with PCR assay were 0.96% and 1.5% respectively. The false positivity of HCV –Ab by ELISA and CIA as compared PCR was 14-6% (6 out of 41) and 26.6% (16 out of 60). Conclusion: Generally, ELISA is more sensitive and specific than Chemiluminescence for blood transfusion screening. But, at gray zone results, PCR should be used as confirmatory method. And so it is very important to screen blood donors using RT–PCR to avoid false positive and false negative results.