From the Guidelines
A reactive HCV AB qualitative test indicates that Hepatitis C virus antibodies have been detected in the blood, suggesting past or present exposure to the virus, but it does not confirm an active infection. This test is a screening tool, not a definitive diagnosis, and follow-up testing with an HCV RNA test is necessary to determine the presence of an active infection 1. The HCV RNA test, also known as a viral load test, will show if the virus is currently active in the body.
Some key points to consider:
- A positive HCV-antibody test can indicate current or past infection, or rarely, a false positive result 1.
- HCV-antibody testing with reflex HCV RNA polymerase chain reaction testing is recommended for initial HCV screening 1.
- Persons with a reactive HCV-antibody test and a negative HCV RNA test should be informed that they do not have evidence of current HCV infection, but they are not protected from reinfection 1.
- Quantitative HCV-RNA testing is recommended prior to initiation of antiviral therapy to document the baseline level of viremia 1.
It's essential to note that many people who test positive for HCV antibodies have cleared the virus naturally without treatment, but the antibodies remain in their system for life. If the follow-up RNA test is positive, it's likely that the person has chronic hepatitis C, and they should consult with a healthcare provider about treatment options, which typically involve direct-acting antiviral medications taken for 8-12 weeks with cure rates exceeding 95% 1. Early detection and treatment are crucial as chronic hepatitis C can lead to serious liver complications, including cirrhosis and liver cancer, if left untreated.
From the Research
Definition of Reactive HCV AB Qualitative
- A reactive HCV AB qualitative test result indicates the presence of antibodies against the hepatitis C virus (HCV) in the blood 2, 3.
- This test is used to detect current or past infection with HCV, but it cannot distinguish between the two 2.
- The test measures the presence of immunoglobulin G (IgG) and/or immunoglobulin M (IgM) antibodies against HCV antigens 4.
Test Methods
- Enzyme-linked immunosorbent assay (ELISA) is a common method used for HCV antibody detection 2, 3.
- Rapid diagnostic tests (RDTs) are also available and have excellent sensitivity and specificity compared to laboratory-based methods 3.
- Reverse-transcription PCR (RT-PCR) is used to detect HCV RNA and confirm the diagnosis of HCV infection 2, 5.
Clinical Significance
- A reactive HCV AB qualitative test result requires further testing, such as RT-PCR, to confirm the diagnosis and determine the presence of active infection 2, 5.
- The test result is essential for diagnosing and managing HCV infection, as well as for determining the appropriate treatment strategy 2, 3.
- HCV genotyping and subtyping testing is also crucial for pre-treatment evaluation and understanding the epidemiology of the virus 2, 6.