What is the next step for a patient with a reactive Hepatitis C (HCV) screen on screening labs?

Management of a Patient with a Reactive Hepatitis C Screen

For a patient with a reactive hepatitis C (HCV) antibody screen, the next step is to order an HCV RNA test (nucleic acid test or NAT) to determine if there is current infection. 1

Testing Algorithm for Reactive HCV Antibody

A reactive HCV antibody result requires follow-up testing to determine if the patient has:

1. Current HCV infection (HCV RNA positive)
2. Past, resolved HCV infection (HCV RNA negative)
3. False positive antibody result (HCV RNA negative)

Step-by-Step Management:

1. Order HCV RNA testing immediately

   • Use the same blood sample if possible (reflex testing)
   • If using OraQuick Rapid Test with fingerstick, obtain a venipuncture sample for RNA testing 1

2. Interpret HCV RNA results:

   • If HCV RNA is detected:

     • Diagnose as current HCV infection
     • Provide appropriate counseling
     • Link patient to medical care and treatment
     • Report to local health department (mandatory in most jurisdictions) 1

   • If HCV RNA is not detected:

     • Indicates either past, resolved infection or false positive antibody
     • No further action required in most cases 1

Special Considerations

• Recent exposure (within 6 months):

  • If recent exposure is suspected but HCV RNA is negative, consider repeat HCV RNA testing or follow-up antibody testing to detect potential seroconversion 1

• Immunocompromised patients:

  • Consider HCV RNA testing even with negative antibody results as immunocompromised patients may not produce detectable antibodies 1

• Distinguishing false positivity from resolved infection:

  • If clinically important to differentiate, consider testing with a second, different HCV antibody assay 1
  • False positivity is unlikely to occur with multiple different antibody tests 1

Common Pitfalls to Avoid

1. Failing to order HCV RNA testing after a reactive antibody test

   • This is the most common gap in laboratory practice, with only 54% of laboratories automatically reflexing to RNA testing 2
   • Patients may be lost to follow-up without complete diagnostic testing

2. Relying solely on antibody optical density values

   • No threshold values can reliably differentiate true from false positive results without RNA testing 3
   • High optical density values (≥2.2) are often associated with true positivity but cannot replace RNA testing 3

3. Unnecessary supplemental antibody testing

   • In patients with chronic liver disease and positive antibody tests, confirmatory antibody tests (like RIBA) are generally unnecessary - proceed directly to HCV RNA testing 4
   • Supplemental antibody tests are more appropriate for low-risk populations like blood donors 4

By following this evidence-based algorithm, you can accurately diagnose or exclude current HCV infection and ensure appropriate patient management and follow-up.