Clinical Information

Laboratory testing for hepatitis C virus (HCV) infection in patients and donors of organ, blood, cells, tissue, and tissue products usually begins by screening for the presence of HCV antibodies (anti-HCV) in serum, using an US Food and Drug Administration or Food and Drug Administration approved anti-HCV screening test. Specimens that are repeatedly reactive by screening tests should be confirmed by more HCV-specific tests, such as direct detection of HCV RNA by the reverse transcriptase-polymerase chain reaction assay or confirmatory detection of HCV antibodies by serologic assays using recombinant HCV-specific antigens. In patients with reactive HCV antibody screening test results but negative or undetectable HCV RNA test results, HCV antibody confirmatory tests would be useful to distinguish between true- and false-reactive HCV antibody screening test results.

HCV antibodies are usually not detectable during the first 2 months following infection, and they are usually detectable by the late convalescent stage (>6 months after onset) of infection. These antibodies do not neutralize the virus, and they do not provide immunity against this viral infection. Loss of HCV antibodies may occur in the years following resolution of infection.

Despite the value of serologic confirmation of HCV infection, several limitations of this test exist:

-There may be a long delay (up to 6 months) between exposure to the virus and development of detectable HCV antibodies, especially in immunocompromised patients

-A positive test result does not distinguish between past (resolved) and chronic HCV infection

-Serologic tests cannot predict or monitor response to antiviral therapy

For more information see Hepatitis C: Testing Algorithm for Screening and Diagnosis.