A positive result for Hepatitis A antibodies indicates your immune system responded to the Hepatitis A virus, either from a past infection or recent exposure. This test measures IgM and IgG antibodies, which appear at different stages of infection.
When you're exposed to the Hepatitis A virus, your immune system produces specific antibodies. The test detects these antibodies in your blood:
The test results show whether these antibodies are present and at what levels. A reactive result means antibodies were detected.
| Test Type | Detected Antibodies | When It's Ordered |
|---|---|---|
| IgM anti-HAV | IgM antibodies | During acute infection |
| Total anti-HAV | Both IgM and IgG | General screening |
| IgG anti-HAV | IgG antibodies | Past infection or vaccination |
Doctors use this test to:
For example, if someone shows symptoms like fatigue, abdominal pain, or jaundice, doctors might order this test to confirm Hepatitis A as the cause.
Another mistake is assuming a reactive result always means an active infection. If only IgG antibodies are present, it likely indicates past infection or vaccination, not current illness.
Last year, I had a patient with vague symptoms who'd recently traveled internationally. We ordered Hepatitis A antibody tests, and the results showed IgM antibodies. This confirmed an acute Hepatitis A infection, allowing us to start appropriate treatment and monitor the patient's recovery.
If your test is reactive, your doctor will: