Clinical Application of Polymerase Chanin Reaction for the Diagnosis of Hepatitis C Virus Infection

Abstract

Current serologic tests for the detection of antibody to hepatitis C virus (anti-HCV) by enzyme immunoassay (EIA) produce occasional false positive reactions and do not provide useful data about the previous status of antibody formation. So, supplementary tests are necessary. Recently, the application of Polymerase Chain Reaction (PCR) for the detection of HCV RNA has been reported for this confirmatory purpose. The authors evaluated the clinical usefulness of this PCR assay as a routine laboratory diagnostic test for the detection of HCV infection. In this study, HCV-PCR assays were performed for 80 samples of liver disease, 27 samples of hemodialysis, and 40 samples of healthy blood donor. These assays utilized nested reverse transcriptase-PCR(RT-PCR) with two pairs of oligonucleotide primers (40S, NTAI, 80S, 300A) based on the 5´-UTR regions. The results were compared to those of tests for anti-HCV by EIA and another two primer pairs (#32, #36, #33, #48). Clinical data including ALT level were also compared.:; The results are as follows: HCV RNA was detected by PCR in 44/80(55%) cases. The comparison of results between PCR and EIA showed concordance in 48/72(67%) cases. Discordance that is negative by PCR but positive by EIA or positive by PCR but negative by EIA, occurred in 18/72(25%) cases and 6/72(8%) cases, respectively. In 6/72(8%) cases of positive by PCR but negative by EIA, the mean value of ALT was 145.3 IU/L, whereas the mean value of ALT was 70 IU/L in 16/72(23%) cases in which both tests were negative. The 40 healthy normal blood donors were all PCR negative. 12/27(44%) cases of hemodialysis patients were positive by PCR, but 9/12(75%) cases were negative by EIA. The comparison between two different primer pair sets showed concordance in 34/40 (85%) and discordance in 6/40 (15%) cases, respectively. In conclusion, PCR assay by simplified nested RT-PCR for the detection of HCV RNA can be a valuable diagnostic tool for the early detection of HCV infection and viremia. But further studies involving more clinical cases, in-depth analysis of possible factors causing false negative or positive reactions, and investigation of the technical aspects of specimen handling should be performed.