From the Guidelines
For a patient with a reactive Hepatitis C antibody test in the setting of known hepatitis C, the next step in workup should be to order an HCV RNA quantitative test (viral load) to confirm active infection. This test directly measures the amount of virus in the blood and will determine if the patient has active hepatitis C infection or if they have cleared the virus naturally or through previous treatment 1.
Importance of HCV RNA Testing
The HCV RNA test is crucial because a positive HCV-antibody test indicates current or past infection, but it does not distinguish between the two 1. According to the 2020 guidelines from the American Association for the Study of Liver Diseases-Infectious Diseases Society of America, HCV RNA testing is necessary to confirm active HCV infection 1.
Additional Testing
If HCV RNA is detected, HCV genotyping to determine the specific strain (genotypes 1-6) is recommended, as this will guide treatment selection 1. Liver function tests (ALT, AST, bilirubin, albumin) and a complete blood count should be performed to assess liver health and for baseline values. A liver fibrosis assessment is also important, either through non-invasive methods like FibroScan or serum markers (FIB-4, APRI), or liver biopsy in select cases. These tests help determine the degree of liver damage and urgency of treatment.
Screening for Co-infections
Screening for hepatitis B and HIV co-infection is recommended as these can complicate management 1. The goal of this workup is to confirm active infection, assess liver damage, and gather information needed to select an appropriate direct-acting antiviral (DAA) regimen, which typically consists of 8-12 weeks of oral therapy with cure rates exceeding 95% 1.
Key Considerations
- Quantitative HCV-RNA testing is recommended prior to initiation of antiviral therapy to document the baseline level of viremia (i.e., baseline viral load) 1.
- HCV genotype testing may be considered for those in whom it may alter treatment recommendations, especially in cases of previous treatment failure 1.
- Liver fibrosis assessment is crucial for determining the degree of liver damage and the urgency of treatment.
- Screening for co-infections such as hepatitis B and HIV is essential for comprehensive management.
From the Research
Next Steps in Workup for Reactive Hepatitis C (HCV) Antibody
- The next step in the workup for a patient with a reactive Hepatitis C (HCV) antibody is to perform an HCV RNA test to confirm the diagnosis of HCV infection 2, 3, 4.
- This is because a reactive HCV antibody test only indicates that the patient has been exposed to the virus at some point in their lives, but it does not distinguish between current and past infection 4.
- The HCV RNA test is the gold standard for diagnosing current HCV infection and is essential for determining the patient's eligibility for treatment 4.
- Automatic reflexive HCV RNA testing of HCV antibody-reactive specimens is recommended to ensure that all patients with current HCV infection are identified and linked to care 2, 3.
- A single-visit sample collection approach is preferred to avoid incomplete testing and ensure that patients are not lost to follow-up 2, 3.
Importance of HCV RNA Testing
- HCV RNA testing is crucial for confirming the diagnosis of HCV infection and determining the patient's treatment eligibility 2, 3, 4.
- The test can detect the presence of HCV RNA in the patient's serum, indicating current infection 4.
- The results of the HCV RNA test can also be used to monitor the patient's response to treatment and determine the effectiveness of antiviral therapy 5, 4.
Clinical Considerations
- The choice of supplementary or confirmatory tests may depend on the clinical setting and the likelihood of a true-positive HCV antibody result 4.
- In patients with chronic liver disease, confirmatory tests are generally unnecessary, but may be indicated in certain situations, such as in blood donors or individuals with normal aminotransferase levels 4.
- Liver histology is the gold standard for assessing the severity of liver disease, and quantitative tests for serum HCV RNA levels do not help determine the severity of liver disease 4.