What Does Reactive Hepatitis A AB, Total Mean?
A reactive (positive) total Hepatitis A antibody test means you have immunity to Hepatitis A virus, indicating either past infection with recovery or successful vaccination. 1
Interpretation of the Result
The presence of total anti-HAV indicates that you have been exposed to HAV at some point in your life, either through natural infection or vaccination, and you are now protected against future HAV infection. 1
- Total anti-HAV antibody persists for life after natural infection and confers lifelong protection against reinfection. 1
- After vaccination, protective antibody levels persist for at least 20-40 years according to kinetic models. 1
- The CDC defines total anti-HAV as indicating immunity to HAV infection, though it does not differentiate between current infection, past resolved infection, or vaccination-induced immunity. 1
What This Result Does NOT Tell You
A positive total anti-HAV result alone cannot distinguish between:
- Current acute hepatitis A infection
- Past resolved hepatitis A infection with natural immunity
- Immunity from hepatitis A vaccination 1
When Additional Testing Is Needed
To determine if this represents a current or past infection, testing for IgM anti-HAV would be necessary. 1
- If IgM anti-HAV is positive: This indicates acute or recent HAV infection, typically within the past 6 months. 1
- If IgM anti-HAV is negative: This indicates either past HAV infection with natural immunity or immunity from HAV vaccination. 1
The CDC notes that IgM anti-HAV typically becomes detectable 5-10 days before symptom onset in acute infection and generally declines to undetectable levels within 6 months after infection. 1
Clinical Implications
No further HAV vaccination is needed for individuals with positive total anti-HAV, as they already have immunity. 1
- You are protected against hepatitis A infection and cannot contract the disease. 1
- For individuals being evaluated for acute hepatitis with positive total anti-HAV, testing for other causes of hepatitis should be considered if IgM anti-HAV is negative. 1
Important Caveat
In rare cases, early acute hepatitis A patients may show anti-HAV IgM non-reactive but total anti-HAV reactive results due to differences in assay sensitivity for detecting IgM antibodies. 2 However, this is uncommon and typically resolves with repeat testing within a few days. 2
Do not confuse HAV antibody testing with HBV antibody testing, which has different interpretation patterns. 1