400 - 500,000 people in the UK are infected with hepatitis C, and more than 80% are unaware.
Hepatitis C causes progressive inflammation in the liver which can lead to cirrhosis, liver failure and cancer. Most people infected have no symptoms until very late in the disease process.
The diagnosis is often prompted by the discovery of abnormal liver function tests, although up to 30% of individuals with hepatitis C actually have normal liver function tests.
The initial antibody test identifies people who have been exposed to the virus, the majority remain infected, which is detected by a PCR test to detect the virus itself.
Of all people infected with hepatitis C 30% will develop cirrhosis 30 years after initial infection, though some people will have significant disease after a much shorter period.
Common sources of infection include a history of injecting drug use, a blood transfusion prior to routine screening in 1991 and being born in the developing world, especially in countries such as Pakistan and Egypt.
Screening blood tests can identify the presence of the virus and look at the subtype or genotype, which influences the treatment.
Ultrasound of the liver is a good screening test to look for advanced liver disease.
Liver biopsy is still believed to be the gold standard for assessing the degree of scarring (fibrosis) that has occurred in the liver.
Non-invasive tests of liver fibrosis such as 'fibroscan' and blood test markers of fibrosis will be used with increasing frequency in the future.
Over 50% of hepatitis C is now cured with antiviral therapy
Treatment consists of combined pegylated interferon and ribavirin.