What does a reactive anti-Hepatitis A Virus (HAV) Immunoglobulin G (IgG) test result mean?

Reactive Anti-HAV IgG Interpretation

A reactive anti-HAV IgG test indicates either past resolved hepatitis A infection or immunity from hepatitis A vaccination, and confirms that you are protected against future hepatitis A infection. 1

What This Result Means

• The presence of anti-HAV IgG antibody signifies immunity to hepatitis A virus, which appears early in the course of infection and remains detectable for your lifetime, providing lifelong protection against the disease. 1

• This antibody can result from two scenarios: either you had hepatitis A infection in the past (which has since resolved), or you received the hepatitis A vaccine. 1

• You are not currently infected with hepatitis A and cannot transmit the virus to others. 1

• IgG anti-HAV persists indefinitely after infection or vaccination, unlike IgM anti-HAV which indicates acute/recent infection and typically becomes undetectable within 6 months. 1

Clinical Significance

• No treatment or monitoring is required for a reactive anti-HAV IgG result, as this simply confirms protective immunity. 1

• You do not need hepatitis A vaccination if you have a reactive anti-HAV IgG, since you already have immunity. Vaccination of someone who is already immune is not harmful, but it is unnecessary. 1

• This protective immunity is lifelong, meaning you will not develop hepatitis A infection in the future. 1

Important Distinctions

• Anti-HAV IgG alone does not indicate acute infection—diagnosis of acute hepatitis A requires detection of IgM anti-HAV antibodies, which appear 5-10 days before symptom onset and indicate current or recent infection. 1

• Total anti-HAV testing (which detects both IgM and IgG together) is commonly used in epidemiologic studies to measure previous infection prevalence, while IgM-specific testing is used to diagnose acute infection. 1

• The commercially available anti-HAV tests measure antibodies from natural infection or vaccination, but cannot distinguish between these two sources of immunity—though this distinction rarely matters clinically since both provide protection. 1