Rapid Immunoassay Alone Is Insufficient for the Detection of Hepatitis C Virus Infection Among High-risk Population

R. Firdaus; K. Saha; P. C. Sadhukhan

Disclosures

J Viral Hepat. 2013;20(4):290-293. 

In This Article

Abstract and Introduction

Abstract

Rapid testing for HCV has become a routine practice in resource-limited settings for initial screening. The objective of this study was to evaluate the performance of rapid immunoassay diagnostic test kits for specific and accurate diagnosis of HCV infection among different patient groups in clinical settings of Kolkata, India. Two hundred and fifty-four randomly selected serum samples of 612 samples reported as HCV nonreactive by rapid immunodiagnostic tests were evaluated for HCV antibody, ELISA and HCV RNA testing for confirmatory diagnosis. 15.74% were HCV seropositive by ELISA, and 11.02% were RNA positive by nested RT-PCR. Additionally, 15 HCV-seronegative chronic liver disease patients with high ALT and AST values were screened for HCV RNA, of which five were positive whose viral load ranged from 1.2 × 102 to 4.4 × 106 IU/mL, and the samples belonged to IVDUs and HIV-co-infected individuals. The results showed that HCV rapid immunoassay test cannot be solely relied on as an absolute and accurate diagnostic tool for screening infection of HCV particularly in high-risk group patients such as IVDUs, haemodialysis, thalassaemic and HIV-co-infected patients who need HCV screening frequently.

Introduction

Hepatitis C virus (HCV) infection is a global health problem affecting around 170 million people worldwide and is a leading cause of liver cirrhosis and hepatocellular carcinoma.[1] In India, HCV infection as a cause of acute viral hepatitis has been reported to vary between 0–21% and responsible for 14–26% cases of chronic liver disease.[1] HCV infection is mostly acquired through transfusion of blood or blood products. A high prevalence of HCV is found in many high-risk groups (HRG) exposed to blood or blood products, like intravenous drug users (IVDUs), patients with paediatric haematologic malignancies and those with thalassaemia and haemophilia. The prevalence of HCV in blood donors in India (1–1.5%) is higher than that in developed countries.[2]

The laboratory diagnosis of HCV infection is based on the detection of circulating antibodies and viral RNA. The most widely used HCV screening tests are ELISA and HCV RNA by nucleic acid test (NAT), as they are the most appropriate for screening large numbers of specimens on a daily basis.[3] These assays are technically demanding and require sophisticated laboratory infrastructure. Hence, in developing countries like India, the blood transfusion centres mostly rely on simple, rapid tests for HCV with individual kits as an inexpensive alternative for ELISA or NAT assays. Although the use of simple rapid immunoassays has significantly reduced the risk of HCV transmission, the window period for the detection of recent or new infection among the high-risk group remains a concern. The purpose of our study was to determine the performance of simple rapid immunoassay in patients who belonged to high-risk group such as thalassaemic and haemodialysis patients, who undergo blood transfusions regularly. As no previous literature is available on the contradictory results of the HCV rapid immunoassay, our study aimed to help the clinicians and the laboratory personnel on false-negative results of the rapid immunoassay, so that in future more confirmatory screening tests would be employed in blood transfusion centres to detect accurately the status of the HCV-positive patients.

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