What does a reactive Hepatitis C Virus (HCV) antibody test result mean?

What Does a Reactive HCV Antibody Test Mean?

A reactive HCV antibody test means you have been exposed to hepatitis C virus at some point, but it does NOT tell you whether you currently have the infection—you must get an HCV RNA test to determine if you have active infection. 1

Three Possible Interpretations of a Reactive Result

According to CDC guidelines, a reactive HCV antibody result indicates one of three scenarios 1:

1. Current (active) HCV infection - You are currently infected and potentially infectious
2. Past resolved infection - You were previously infected but your body cleared the virus
3. False positive result - The test was incorrectly positive (no actual HCV exposure)

Critical Next Step: HCV RNA Testing Required

You cannot stop at the antibody test alone. The CDC explicitly states that a reactive antibody result should be immediately followed by HCV RNA testing (also called nucleic acid testing or NAT) to distinguish between these three possibilities 1.

How to Interpret the Complete Testing Sequence:

• HCV antibody reactive + HCV RNA detected = Current active infection requiring treatment 1
• HCV antibody reactive + HCV RNA NOT detected = Either past resolved infection OR false positive antibody test 1

Why the Antibody Test Alone Is Insufficient

The HCV antibody test has important limitations 1:

• False positive rates are significant: In low-risk populations (general population, healthcare workers, blood donors), approximately 35% of reactive antibody tests are false positives (range 15-60%) 1
• Even in immunocompromised populations (like dialysis patients), about 15% of reactive results are false positives 1
• The antibody persists after cure: If you previously had HCV and cleared it (either spontaneously or with treatment), the antibody typically remains detectable for life 1

Recommended Testing Approach

The most current CDC guidance (2013) recommends single-visit sample collection to ensure complete testing 1, 2:

• Blood should be drawn once, with automatic reflex to HCV RNA testing if the antibody is reactive 1
• This prevents the common problem of "incomplete testing" where patients never return for RNA confirmation 2
• Approximately one-third of patients historically had incomplete testing when multiple visits were required 2

Special Circumstances to Consider

Recent Exposure (Within 6 Months)

If you were potentially exposed to HCV within the past 6 months, the antibody test may still be negative even if you're infected (the "window period") 1. In this scenario, direct HCV RNA testing should be performed 1.

Immunocompromised Patients

If you have a weakened immune system, you may not produce detectable antibodies despite active infection 1. HCV RNA testing should be considered in immunocompromised individuals even with negative antibody results 1.

What Happens If RNA Is Detected

If HCV RNA is detected, this confirms current active infection and you should 1:

• Receive appropriate counseling about transmission prevention
• Be linked to medical care for evaluation
• Be considered for curative antiviral therapy
• Have liver disease assessment (such as ALT levels)

Bottom Line for Clinical Action

Do not rely on the antibody test alone to determine infection status. The CDC explicitly warns against this practice 1. The reactive antibody result is only the first step—HCV RNA testing is mandatory to determine whether you have active infection requiring treatment versus past resolved infection or a false positive result 1.