Results vary with the individual laboratory. Decisions regarding initiating treatment also vary with the risk group. If the RIBA is indeterminate or negative, hepatitis C is unlikely. The progress of therapy is monitored by RNA tests. The qualitative PCR test, the most sensitive test currently available, detects HCV viremia, expressed as present or absent.
Quantitative assays measure viral particles.
This is particularly important when viral counts are low. Disease severity can be determined by liver parameters, clinical parameters, and the results of liver biopsy. Genotype and viral load do not correlate with disease severity. Supplemental assays such as RIBA may be helpful in low-risk groups. HCV RNA by qualitative PCR or a very sensitive quantitative PCR is useful in diagnosis and treatment, but no hepatitis C test predicts the severity of the liver disease.