Hepatitis A – Serology

Consistent with O. Reg. 671/92 of the French Language Services Act, laboratory testing information on this page is only available in English because it is scientific or technical in nature and is for use only by qualified health care providers and not by members of the public.

Background
This page provides testing information for hepatitis A virus (HAV) serology at Public Health Ontario (PHO), including HAV IgM and IgG. For information regarding other testing options, refer to the following PHO webpages:

Hepatitis A – Genotyping-Subtyping

Updates

Added webpage for Hepatitis A – Genotyping-Subtyping
Added an interpretation table
Updated the submission and collection notes to outline ordering instructions for HAV serology

*Uncontrolled print copy. Valid only on day of print: 12 Nov 2025.

Testing Indications

Testing for hepatitis A virus (HAV) serology may be indicated:

for the investigation of patients with suspected acute viral hepatitis
to determine immune status (note: post-vaccine serologic testing is not routinely recommended)
as part of an epidemiologic investigation (e.g. outbreak investigation).

Acceptance/Rejection Criteria

Donor testing is not available through PHO’s laboratory. Specimens from patients being screened as potential donors (e.g. organ, tissue, cells, fertility, etc.) should be referred to a laboratory that performs donor screening assays. Specimens received for donor screening at PHO’s laboratory will be rejected.
Specimens beyond 14 days from date of collection will not be tested.

Specimen Collection and Handling

Specimen Requirements

Test Requested

Required Requisition(s)

Specimen Type

Minimum Volume

Collection Kit

Hepatitis A Serology

General Test Requisition

Serum

IgG only: 1 mL

IgM only or

IgM+IgG: 2 mL

Serum Separator Tube (SST)

Submission and Collection Notes

PHO prefers centrifuged SST for serological testing. Generally, only one FULL draw 5 mL SST is needed for testing a combination of up to six infectious disease serology markers. If a full tube cannot be drawn, submit two tubes. If there is a high clinical suspicion that the patient has an HCV infection and testing for other serological markers is needed, consider submitting two SST to ensure there is adequate volume. Refer to Serology Testing – Laboratory Specimen Collection and Submission Instructions for more information.

Do not submit glass tubes.

Label the specimen container(s) with the patient’s first and last name, date of collection and one other unique identifier such as the patient’s date of birth or Health Card Number. For additional information see: Criteria for Acceptance of Patient Specimens. Failure to provide this information may result in rejection or testing delay.

ALL sections of the General Test Requisition must be completed by authorized health care providers for each specimen submitted, or testing may be delayed or cancelled. Please follow instructions for HAV serology test ordering below.

Requisition selection(s)	Tests Performed	Notes
Immune Status	HAV IgG
Acute Infection	HAV IgM	Clinical information pertaining to acute viral hepatitis must be provided. If missing, only HAV IgG will be performed.
Acute infection and Immune Status	HAV IgG HAV IgM	Indicate clinical information pertaining to a recent HAV exposure, outbreak investigation, contact with known case etc. under ‘Relevant Exposure(s)’ Clinical information and/or exposure information (if asymptomatic) must be provided. If missing, only HAV IgG will be performed.

Requisition selection(s)

Tests Performed

Notes

Requisition Demonstration

Immune Status

HAV IgG

Acute Infection

HAV IgM

Clinical information pertaining to acute viral hepatitis must be provided. If missing, only HAV IgG will be performed.

Hep A-2a Acute Infection

Hep A-2b Acute Infection

Acute infection and

Immune Status

HAV IgG

HAV IgM

Indicate clinical information pertaining to a recent HAV exposure, outbreak investigation, contact with known case etc. under ‘Relevant Exposure(s)’

Clinical information and/or exposure information (if asymptomatic) must be provided. If missing, only HAV IgG will be performed.

Hep A-3a Acute Infection and Immune Status

Timing of Specimen Collection

HAV IgM is detectable within 2-4 weeks of infection (5-10 days before the onset of symptoms), peaks within 1-2 months and and may persist for up to 6 months. In rare instances, it can be detected for up to 1 year after an acute infection.

HAV IgG begins to rise at the onset of clinical illness and persists for life.

Limitations

HAV IgM may be detected due to cross-reactivity to non-specific antibody, therefore testing should only be done for individuals with symptoms of acute hepatitis A or who have been exposed to HAV. HAV IgM can also be detected in individuals recently vaccinated with the hepatitis A vaccine.

Haemolysed, icteric, lipemic or microbially contaminated serum is not recommended for testing.

Storage and Transport

Store specimens at 2-8°C following collection and centrifugation and ship to PHO’s laboratory on ice packs within 3 days of collection. If delayed shipping is anticipated, remove serum from clot and store frozen at -20°C or colder and ship on dry ice. Place specimen tube in biohazard bag and seal. Place completed General Test Requisition in the pouch at the front of the biohazard bag. All clinical specimens must be shipped in accordance to the Transportation of Dangerous Good Act.

Requisitions and Kit Ordering

Test Frequency and Turnaround Time (TAT)

HAV serology testing is performed daily Monday to Friday at PHO’s laboratory. Turnaround time is up to 3 business days from receipt at PHO’s laboratory.

HAV genotyping is performed at the National Microbiology Laboratory (NML). Refer to Hepatitis A – Genotyping-Subtyping for more information

Test Methods

Specimens for HAV serology are tested using a chemiluminescent microparticle immunoassay (CMIA) for the qualitative detection of IgG and/or IgM antibodies.

Algorithm

Refer to the HAV serology test ordering instructions above for when IgM and IgG are tested.

All positive HAV IgM specimens are automatically sent to the National Microbiology Laboratory for RNA detection and genotyping.

Interpretation

The following table provides possible test results with associated interpretations:

Hepatitis A IgG Result	Hepatitis A IgM Result	Interpretation
Non-reactive	Not tested	No evidence of immunity.
Reactive	Not tested	Evidence of immunity.
Not tested	Non-reactive	No evidence of recent infection/recent vaccination.
Not tested	Reactive	Evidence of recent infection or vaccination.
Non-reactive	Non-reactive	No evidence of immunity. No evidence of recent infection/recent vaccination
Reactive	Non-reactive	Evidence of immunity. No evidence of recent infection/recent vaccination
Non-reactive	Reactive	Evidence of recent infection or vaccination.
Reactive	Reactive	Evidence of recent infection or vaccination

A positive result for HAV IgM with or without a positive HAV IgG suggests recent/acute infection with HAV. It may also be due to non-specificity of the test assay as a result of non-specific cross-reacting antibodies (e.g. rheumatoid factor, polyclonal antibody, etc.). A positive HAV IgM must be interpreted with clinical symptoms and/or exposure history.

Reporting

Results are reported to the physician, authorized health care provider (General O. Reg 45/22, s.18) or submitter as indicated on the requisition.

Specimens that are reactive for HAV IgM are reported to the Medical Officer of Health as per the Ontario Health Protection and Promotion Act.

Due to changes in both PHO’s and Ontario’s laboratory information systems, cumulative reporting is no longer available.