Diagnostic Modalities of Hepatitis C Infection

Abstract

Hepatitis c virus (HCV) is one of the most prevalent blood-borne human pathogens. About 3% of the total world population are HCV infected. According to World Health Organization (WHO), annually there are about 3-4 million new cases of infection. HCV as an extremely prevalent cause of chronic hepatitis which is in turn an underlying condition preceding the progress to cirrhosis and hepatocellular carcinoma (HCC). The aim of HCV diagnosis is ultimately prevention of further viral transmission through identification of infected cases who can furtherly share in spreading viral infection. The usual diagnostic scheme of viral infections includes clinical markers, biochemical markers and virological markers. Most of acute HCV infections are not presented with clinical symptoms and the acute infectious period passes asymptomatic, so clinical markers cannot be relied upon for HCV diagnosis. Regarding biochemical markers which can be reflected as the changes of levels of liver enzymes, mainly the alanine aminotransferase enzyme (ALT), it cannot be relied upon as well, as in many cases of HCV infection ALT level remain normal in the same time when HCV RNA can be detected, which is a reflection of HCV viremia and active infection. The most reliable in diagnosis is the use of virological markers which can be detected by two general methodologies, direct and indirect methods. Indirect methods are the tests where anti HCV antibodies are detected, where IgM indicates current infection and IgG indicates current or past infection. Whereas direct methods are the detection of the virus itself by isolation, detection of the viral immunological fingerprint, namely viral antigens, and the detection of viral molecular fingerprint, namely viral RNA.