What does a reactive Hepatitis C Antibody (Hep C AB) test result indicate in a patient?

What Does a Reactive Hepatitis C Antibody Test Mean?

A reactive Hepatitis C antibody (HCV AB) test means that antibodies to hepatitis C virus have been detected in your blood, indicating one of three possibilities: current active HCV infection, past resolved infection, or a false-positive result. 1

Immediate Next Step Required

You cannot stop at a reactive antibody test alone—you must proceed immediately to HCV RNA testing (nucleic acid testing/NAT) to determine if you have active infection. 1 The CDC explicitly states that a reactive HCV antibody result should be followed by testing for HCV RNA to distinguish between these three scenarios. 1

What the Follow-Up HCV RNA Test Will Tell You

If HCV RNA is Detected (Positive):

• This indicates current, active HCV infection requiring medical evaluation and consideration for antiviral treatment 1
• Most persons with detectable HCV RNA have chronic HCV infection 1
• You are infectious to others and need counseling about transmission prevention 1
• You need referral to a specialist for liver disease assessment and treatment options 1

If HCV RNA is Not Detected (Negative):

• This indicates no current HCV infection 2
• The reactive antibody represents either:
  • Past resolved infection (15-25% of acute HCV infections clear spontaneously) 2
  • Successful past treatment that cleared the virus 2
  • False-positive antibody test (occurs in approximately 35% of reactive results in low-prevalence populations) 1, 2
• You are not infectious to others 2
• No treatment is needed 2
• No further testing is typically required 2

Important Clinical Caveats

When Repeat HCV RNA Testing IS Needed:

The CDC specifies only these specific situations require repeat RNA testing when initially negative: 1, 2

• Recent exposure within the past 6 months (antibodies may not yet be detectable, but RNA can be positive as early as 1-2 weeks post-exposure) 1
• Immunocompromised patients (may have delayed or absent antibody response despite active infection) 1
• Clinical evidence of active liver disease despite negative RNA 1
• Concerns about specimen handling or storage 1

False-Positive Antibody Results Are Common in Low-Risk Populations:

• Among populations with HCV prevalence <10% (blood donors, general population, healthcare workers), approximately 35% of reactive antibody tests are false-positives (range 15-60%) 1
• This is why confirmatory RNA testing is critical—you cannot rely on antibody testing alone 1

Key Counseling Points

• HCV antibodies do not provide protective immunity—if the reactive antibody represents past resolved infection, you can be reinfected if exposed again 2
• The antibody test detects exposure to HCV but cannot distinguish timing or current infection status 1
• Only HCV RNA testing definitively identifies who needs treatment and who is infectious 1

Testing Logistics

The recommended approach is reflex testing: the same blood sample used for initial antibody testing should automatically proceed to HCV RNA testing if reactive, without requiring another blood draw 1