Testing for Anti-HAV and Anti-HEV Antibodies
Yes, both anti-HAV and anti-HEV antibody tests are routinely performed and are essential diagnostic tools for detecting hepatitis A and E virus infections. These serological tests are widely available and play a critical role in diagnosing acute and past infections with these viruses.
Anti-HEV Testing
All patients presenting with biochemical evidence of hepatitis should be tested for HEV as part of first-line virological investigation, irrespective of travel history. 1
Testing Methodology for HEV
Antibody detection (anti-HEV IgM and IgG) is performed using enzyme immunoassays in combination with nucleic acid testing (NAT) for optimal diagnosis 1
Anti-HEV IgM appears first around the time of clinical onset and is relatively short-lived (usually 3-4 months, but may persist up to a year) 1
Anti-HEV IgG follows soon after IgM and provides a long-lasting response with increasing antibody avidity over time 1
Important caveat: Anti-HEV IgM alone is not sufficiently robust for diagnosis due to suboptimal specificity of certain assays 1
Recommended Diagnostic Approach for HEV
The European Association for the Study of the Liver (EASL) recommends using a combination of serology and NAT testing to diagnose HEV infection. 1
For acute HEV infection: Detect anti-HEV antibodies (IgM, IgG or both) by enzyme immunoassays combined with HEV NAT 1
For chronic HEV infection: NAT testing is essential, as anti-HEV antibodies are often undetectable in immunosuppressed patients 1
Chronic hepatitis E is defined as HEV RNA being detectable for at least three months 1
Clinical Context for HEV Testing
Acute hepatitis E is the commonest cause of acute viral hepatitis in many countries, making first-line testing critical 1
Testing should not be delayed until HAV, HBV, and HCV results are negative—this outdated approach is no longer appropriate 1
Patients with suspected drug-induced liver injury (DILI) should be tested for HEV, as 13% of presumed DILI cases were actually acute hepatitis E in one UK cohort 1
Anti-HAV Testing
Anti-HAV antibody testing is performed to diagnose hepatitis A virus infection, with both IgM and IgG antibodies detected by enzyme immunoassays. 2
Testing Methodology for HAV
Anti-HAV IgM is the acute-phase serological marker that provides clear indication of acute HAV infection 2
Anti-HAV IgG indicates past infection or immunity 2
Testing is typically performed using microparticle enzyme immunoassay (MEIA) or similar enzyme-linked immunosorbent assays 3, 4
Important Clinical Consideration for HAV Testing
Anti-HAV IgM testing should only be performed when hepatic aminotransferases (ALT/AST) are elevated. 3
In a prospective study, 82% of patients with elevated ALT/AST were anti-HAV IgM reactive 3
Among patients with normal AST/ALT levels, none were anti-HAV IgM reactive (except those on follow-up for confirmed HAV infection) 3
This means ordering anti-HAV IgM when liver enzymes are normal is unnecessary and wasteful 3
Seroprevalence Context
Overall seroprevalence of anti-HAV can be high (84.3% in some populations), with seropositivity associated with age, occupation, location, and ethnicity 4
The age at which 50% of the population becomes seropositive varies significantly by geographic location (12-26 years in different regions) 4
Diagnostic Performance
For anti-HEV IgG: Sensitivity of 86.7% and specificity of 92.1% for diagnosing acute hepatitis E 5
For anti-HEV IgM: Sensitivity of 53.3% and specificity of 98.6% for diagnosing acute hepatitis E 5
For anti-HAV IgM: Detection rate of 96.9-100% in acute hepatitis A patients, depending on timing of sample collection 6
Key Pitfalls to Avoid
Do not rely on anti-HEV IgM alone for diagnosis due to suboptimal specificity 1
Do not order anti-HAV IgM when liver enzymes are normal—it provides no diagnostic value 3
Do not delay HEV testing until other hepatitis viruses are ruled out, as HEV is now the most common cause of acute viral hepatitis in many developed countries 1
Be aware that some assays lack sensitivity, which has historically resulted in significant underestimates of population exposure to HEV 1