Hepatitis - Hepatitis C

Specific Tests for Identifying Hepatitis C and Determining its Severity

Tests for Liver Enzymes. Blood tests showing elevated liver enzymes, particularly alanine aminotransferase (ALT), plus symptoms of hepatitis (e.g., jaundice, fatigue) are often first signs of acute hepatitis. In chronic hepatitis, however, liver enzymes may be normal or fluctuate. They also can be elevated even after the virus has cleared.

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Tests to Identify the Virus. The standard first test for diagnosing hepatitis C is known as enzyme-linked immunosorbent assay (ELISA or EIA). The antibody for hepatitis C is used to identify virus but it may not show up for six weeks to a year after the onset of the disease, so its absence is not necessarily an indication of a healthy liver. A test called an immunoblot assay (called RIBA) may also be used to confirm the presence of the virus. An accurate home test (Hepatitis C Check) is now available. It supplies a lancet for obtaining a drop of blood, which is sent to the laboratory for EIA and possibly RIBA analysis. Results take about a week.

Tests to Identify Genetic Types and Viral Load. Additional tests called HCV RNA assays may be used to confirm the diagnosis. They use a polymerase chain reaction (PCR) to detect the RNA (the genetic material) of the virus. Such tests may be performed if there is some doubt about a diagnosis but the physician still firmly believes the virus is present.

HCV RNA assays also determine virus levels (called viral load). Such levels do not reflect the severity of the condition or speed of progression, as they do for other viruses, such as HIV. However, high viral loads suggest a poorer response to treatment with interferons.

Such techniques may also be used to determine the genotype of the virus, which can be helpful in determining a treatment approach. There are six main genetic types of HCV and more than 90 subtypes. They do not appear to affect the rate of progression of the disease itself, but they can differ significantly in their effects on response to treatment. Genotype 1 is the most difficult to treat and is the cause of up to three quarters of the cases in the US. The other common genetic types are types 2 (15%) and 3 (7%), which are more responsive to treatment.

Liver Biopsy. Only a biopsy can determine the extent of injury in the liver. Some experts are now recommending biopsies for all chronic hepatitis C patients, regardless of severity, because of the risk for liver damage even in patients without symptoms. If a biopsy does not show any scarring and liver enzymes are normal, patients can be assured that the outlook is very favorable.