What is the next step in management for a patient with a reactive Hepatitis C (HCV) antibody test?

Management of Reactive Hepatitis C Antibody Test

For patients with a reactive Hepatitis C (HCV) antibody test, the next step in management is to perform HCV RNA testing (nucleic acid testing or NAT) to determine if there is current infection. 1

Understanding HCV Antibody Results

A reactive HCV antibody test can indicate three possible scenarios:

1. Current HCV infection
2. Past HCV infection that has resolved
3. False-positive result

Only HCV RNA testing can distinguish between these possibilities, which is crucial for proper patient management.

Testing Algorithm

Step 1: Confirm Current Infection Status

• Order HCV RNA testing (NAT) immediately after receiving a reactive HCV antibody result
• Single-visit sample collection is strongly recommended to avoid incomplete testing 2
  • Either reflex testing using the same blood sample
  • Or collecting two specimens during the same visit (one for antibody testing, one for potential RNA testing)

Step 2: Interpret Results Based on RNA Testing

• If HCV RNA is detected:

  • Diagnosis: Current HCV infection
  • Action: Provide appropriate counseling and link patient to medical care and treatment 1
  • Before initiating antiviral therapy, confirm HCV RNA positivity with a second test

• If HCV RNA is not detected:

  • Diagnosis: No current HCV infection
  • Interpretation: Either past resolved infection or false-positive antibody test
  • Action: In most cases, no further testing is required 1

Special Considerations

Recent Exposure

• For patients with possible HCV exposure within the past 6 months:
  • Consider repeat HCV RNA testing even if initial RNA test is negative
  • Antibody may not have developed yet in acute infection 1

Immunocompromised Patients

• Consider direct HCV RNA testing in immunocompromised patients
• These patients may have false-negative antibody results 1

Distinguishing False Positives from Resolved Infections

• If clinically important to differentiate between past resolved infection and false-positive:
  • Consider testing with a second, different HCV antibody assay 1
  • False positivity is unlikely to be exhibited by multiple tests with different antigens and platforms 1

Clinical Implications

• Approximately 22-32% of reactive HCV antibody tests may be false-positives in low-prevalence populations 3
• Only about 51% of those with reactive antibody tests have current infection 3
• Incomplete testing (not following antibody testing with RNA testing) occurs in approximately one-third of cases 2

Reporting Requirements

• Both "acute hepatitis C" and "hepatitis C (past or present)" are nationally notifiable conditions
• Positive results from both HCV antibody and HCV RNA testing are reportable to health departments in most jurisdictions 1

Common Pitfalls to Avoid

1. Incomplete testing: Failing to perform HCV RNA testing after a reactive antibody test is a major barrier to proper diagnosis and treatment 2, 4

2. Multiple-visit testing: Requiring patients to return for RNA testing leads to loss to follow-up and missed diagnoses 4

3. Misinterpreting antibody results: A reactive antibody test alone cannot distinguish between current infection, past infection, or false-positive results 1

4. Delayed linkage to care: Patients with confirmed current infection should be promptly referred for evaluation and treatment to prevent disease progression 1

By following this evidence-based algorithm, clinicians can ensure accurate diagnosis and appropriate management of patients with reactive HCV antibody tests, ultimately improving outcomes related to morbidity, mortality, and quality of life.