Hepatitis C Diagnosis

Diagnosis

Serologic profile of Hepatitis C infection

There are a number of diagnostic tests for hepatitis C including: HCV antibody enzyme immunoassay or ELISA, recombinant immunoblot assay, and quantitative HCV RNA polymerase chain reaction (PCR).HCV RNA can be detected by PCR typically one to two weeks after infection, while antibodies can take substantially longer to form and thus be detected.
Chronic hepatitis C is defined as infection with the hepatitis C virus persisting for more than six months based on the presence of its RNA. Chronic infections are typically asymptomatic during the first few decades, and thus are most commonly discovered following the investigation of elevated liver enzyme levels or during a routine screening of high risk individuals. Testing is not able to distinguish between acute and chronic infections.

Serology

Hepatitis C testing typically begins with blood testing to detect the presence of antibodies to the HCV using an enzyme immunoassay. If this test is positive, a confirmatory test is then performed to verify the immunoassay and to determine the viral load. A recombinant immunoblot assay is used to verify the immunoassay and the viral load is determined by a HCV RNA polymerase chain reaction. If there are no RNA and the immunoblot is positive it means that the person had a previous infection but cleared it either with treatment or spontaneously; if the immunoblot is negative, it means that the immunoassay was wrong. It takes about 6–8 weeks following infection before the immunoassay will test positive. A number of tests are available as point of care testing which means that results are available within 30 minutes.
Liver enzymes are variable during the initial part of the infection and on average begin to rise at seven weeks after infection. Liver enzymes are poorly correlated with disease severity.

Biopsy

Liver biopsies are used to determine the degree of liver damage present; however, there are risks from the procedure. The typical changes seen are lymphocytes within the parenchyma, lymphoid follicles in portal triad, and changes to the bile ducts. There are a number of blood tests available that try to determine the degree of hepatic fibrosis and alleviate the need for biopsy.

Screening

It is believed only 5–50% of those infected in the United States and Canada become aware of their status. Testing is recommended in those at high risk, which includes those with tattoos.Screening is also recommended in those with elevated liver enzymes as this is frequently the only sign of chronic hepatitis. Routine screening is not currently recommended in the United States. However, in 2012, the U.S. Centers for Disease Control and Prevention (CDC) recommended a single screening test for those born between 1945 and 1965