Hepatitis C

Of interest is the fact that the origins of this virus is obscure, and had eluded identification for many years. A blood test for HCV identification was developed in 1990 and refined in 1992.

The various blood tests available for HCV diagnosis are based on detection of antibody against HCV (EIA or enzymeimmunoassay and Recombinant immunoblot assays ( RIBAs ). Positive results means previous exposure to the hepatitis C virus. There are tests which detect the genetic material of the virus directly (polymerase chain reaction or PCR method) and this is a much more accurate blood test than antibody based test. EIA is inexpensive, reproducible and has been automated. It is a useful screening test. It's main failing is that is may not always be specific enough and false positive results can occur. This means positive results even the individuals do not have the infection. In a low risk population like in Singapore, a negative EIA test is sufficient to rule out infection. However if EIA is positive, RIBA is used to confirm the diagnosis of HCV infection.

Another test done routinely is liver function tests. If these liver enzymes (ALT, AST) are elevated, it would indicate that there is liver inflammation. If this process is allowed to go unchecked, it will result in cirrhosis and liver cancer in the long run. Active liver disease caused by HCV requires further treatment to reduce the viral load.

It is necessary to extract a small sample of the liver by a process known as a liver biopsy for further examination in the laboratory. By studying the liver tissue, one is able to assess the degree of inflammation and damage to liver. Liver biopsy is the gold standard for assessment of the activity of chronic hepatitis C. When combined with liver function tests, one can assess the severity or activity of the disease and institute treatment if necessary.

Who should be tested for Hepatitis C virus (HCV) infection?

Individuals who :

• Have had blood or blood product transfusion
• Are on haemodialysis
• Have had multiple sexual partners
• Are spouses or close household contacts of hepatitis C patients
• Are organ transplant recipients
  
• Share instruments for cocaine usage (eg. straws for snorting cocaine)