What is the recommended initial test for screening blood for Hepatitis C (HCV)?

Initial Screening Test for Hepatitis C Virus (HCV)

The recommended initial test for screening blood for Hepatitis C is HCV-antibody testing with reflex HCV RNA polymerase chain reaction testing. 1

Testing Algorithm for HCV Screening

Step 1: Anti-HCV Antibody Testing

• Use an FDA-approved enzyme immunoassay (EIA) or point-of-care test for initial screening
• Laboratory-based assays or rapid diagnostic tests (RDTs) can both be used
• The OraQuick HCV Rapid Antibody Test is the only FDA-approved point-of-care test, with sensitivity and specificity similar to laboratory-based assays 1

Step 2: Reflex Testing for Active Infection

• If anti-HCV antibody test is positive, automatically reflex to HCV RNA testing on the same sample
• This "reflex testing" approach requires only a single blood collection and avoids the need for a return visit for confirmatory testing 1
• Reflex testing has been shown to substantially increase the proportion of anti-HCV antibody-positive patients who are tested for viremia and receive subsequent linkage to care 1

Interpretation of Results

1. Anti-HCV antibody negative: No HCV antibody detected, indicating no infection (except in window period or immunocompromised patients)
2. Anti-HCV antibody positive, HCV RNA positive: Indicates current (active) HCV infection
3. Anti-HCV antibody positive, HCV RNA negative: Indicates either:
   • Past, resolved HCV infection
   • False positive antibody result (rare)

Special Considerations

• Recent exposure: For persons who might have been exposed to HCV within the past 6 months, HCV RNA testing or follow-up HCV antibody testing 6+ months after exposure is recommended 1
• Immunocompromised patients: Consider direct HCV RNA testing as antibody response may be delayed or absent 1
• Risk of reinfection: For persons with previous spontaneous or treatment-related viral clearance, HCV RNA testing is recommended since antibody will remain positive 1

Collection Methods

• Standard venipuncture for serum/plasma is preferred
• Dried blood spots (DBSs) can be used as an alternative when:
  • Venipuncture is difficult
  • In remote settings where cold chain transport is unavailable
  • For sequential HCV antibody and reflex HCV RNA testing 1

Quality Considerations

• Use FDA-approved quantitative or qualitative HCV RNA assays with detection level ≤25 IU/mL 1
• The sensitivity of HCV antibody tests has improved with each generation, with current third-generation tests containing antigens from the HCV core, nonstructural 3, nonstructural 4, and nonstructural 5 genes 2

Pitfalls to Avoid

• Failure to reflex test: Not automatically testing HCV RNA after a positive antibody test is a major barrier in the continuum of care 1
• Misinterpretation of results: A positive antibody test alone does not confirm active infection
• Window period: Antibody tests may be negative during the first 6 months after infection
• Immunocompromised patients: May have false-negative antibody tests despite active infection

By implementing this two-step approach with reflex testing, healthcare providers can accurately identify patients with active HCV infection, enabling timely intervention to prevent complications of HCV-related liver disease and reduce transmission.