What does a reactive hepatitis C antibody (HCV AB) test result indicate?

What Does a Reactive Hepatitis C Antibody Test Mean?

A reactive hepatitis C antibody (HCV AB) test indicates that antibodies to hepatitis C virus are present in your blood, but this does NOT automatically mean you have active hepatitis C infection—it requires immediate follow-up with HCV RNA testing to determine if you have current infection, past resolved infection, or a false-positive result. 1, 2

Three Possible Interpretations

A reactive HCV antibody test has three distinct possibilities 2:

• Current active HCV infection - You are currently infected and the virus is actively replicating
• Past resolved infection - You were previously infected but your body cleared the virus (occurs in 15-25% of acute infections) or you were successfully treated 3
• False-positive result - The test is incorrectly showing reactive when you were never infected

Why You Cannot Stop at the Antibody Test

The critical issue is that even with >99% specificity, false-positive results are common in low-prevalence populations, averaging approximately 35% (range 15-60%) of reactive results. 1 This means that in general population screening, more than one-third of reactive antibody tests may be false positives. 1

The CDC explicitly states that you should not rely exclusively on a screening-test-positive result to determine HCV infection status. 1

Required Next Step: HCV RNA Testing

You must proceed immediately to HCV RNA testing to determine your actual infection status. 2 This is the only way to definitively identify who needs treatment and who is infectious. 2

If HCV RNA is Detected (Positive):

• You have current, active HCV infection requiring medical evaluation and consideration for antiviral treatment 2
• Most individuals with detectable HCV RNA have chronic HCV infection 2
• You are infectious to others and need counseling about transmission prevention 2
• Additional testing for liver disease (such as ALT) is indicated 1

If HCV RNA is Not Detected (Negative):

• You have NO current HCV infection 3
• The reactive antibody represents either past resolved infection, successful past treatment, or a false-positive antibody test 3, 2
• You are NOT infectious to others and do NOT require treatment 3, 2
• No further testing is typically required 3, 2

Important Caveats About Timing

False-negative antibody results can occur during the first weeks after infection before antibody is detectable, although HCV RNA can be detected as early as 1-2 weeks after exposure. 1 If you have had a recent exposure within the past 6 months, repeat HCV RNA testing may be indicated even if initial RNA is negative. 3, 2

Optional Confirmatory Antibody Testing

If you want definitive clarification about whether the reactive antibody represents true past infection versus false positivity, supplemental testing with RIBA (recombinant immunoblot assay) can be performed. 1 A positive RIBA confirms true antibody positivity, while a negative RIBA indicates a false-positive screening test. 1

Critical Point About Immunity

HCV antibodies do NOT provide protective immunity—if this represents past resolved infection, you can be reinfected if exposed again. 3, 2 The antibody test only detects exposure to HCV but cannot distinguish timing or current infection status. 2