Laboratory Evaluation of Hepatitis C Virus Infection in Patients Undergoing Hemodialysis from North East India

Abstract

Introduction: Subjects undergoing hemodialysis have enhanced vulnerability to hepatitis C virus (HCV) infection due to invasive procedures and poor infection control practices. Early detection and treatment are essential to prevent cross-infection and mortality/morbidity. However, common use anti-HCV antibody tests lack the necessary accuracy, and alternative tests (e.g. core antigen detection kits) which are available need to be examined as a viable alternative.

Method: A total of 270 continuous serum samples were collected from patients undergoing dialysis within 15 months of study period. Sequentially, multiple tests were performed - immunochromatography-based rapid test, third-generation ELISA i.e. (anti-HCV antibody detection), fourth-generation ELISA (HCV antigen-antibody combined detection assay), and HCV RNA quantitative real time polymerase chain reaction (qPCR) assay. Diagnostic parameters of serological kits were compared in terms of sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), accuracy, and so on. Statistical Package for the Social Sciences was used.

Results: HCV-combined core antigen-antibody assays performed better than other serological assays in reference to the gold standard HCV RNA. This fourth-generation assay yielded a Kappa value of 0.947 compared with the value of 0.747 and 0.619 for anti-HCV ELISA and rapid detection test. Other parameters such as sensitivity, specificity, PPV, NPV, and so on were also better for fourth-generation ELISA compared with third-generation ELISA and other serological assays. HCV RNA was negative in 7.3% of anti-HCV-positive patients and was detected in 11.4% of anti-HCV ELISA-negative patients. In about 1.6% of HCV RNA-positive cases, fourth-generation ELISA was negative and had low HCV viral load (650 IU/ml and below). Fourth generation ELISA detected additional 7.4% HCV positive cases (compared to third generation kits) and upon cost effective analyis, additional cost to be bear for the better detection (by fourth generation kit) was found to be only INR 27 per 1% increased case detection.

Conclusion: In resource scant setup, screening and follow-up of patients undergoing hemodialysis can be performed by fourth-generation HCV ELISA (antigen-antibody combined assay) instead of the current practice of anti-HCV antibody ELISA. Better yield in detection rate will compensate for slight addition to costs.

Keywords: ALT, alanine aminotransferase; AST, aspartate aminotransferase; CI, confidence interval; GGT, gamma-glutamyl transferase; HBV, hepatitis B virus; HBsAg, hepatitis B virus surface antigen; HCV RNA; HCV core antigen; HCV, hepatitis C virus; HIV, human immunodeficieny virus; ICT, immunochromatography; LQ, lower quartile; NAT, nucleic acid amplification test; NPV, negative predictive value; OCI, occult hepatitis infection; PCR, polymerase chain reaction; PPV, positive predictive value; PWID, persons who inject drug; RDT, rapid detection test; SD, standard deviation; UQ, upper quartile; anti-HCV antibodies; dialysis patient; viral load.

Figure 1

Flow diagram of the study.