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Serum Antibody to Hepatitis A Virus (IgM) – Immunoassay

Published: August 9, 2026Updated: August 16, 2026

This test detects the presence of IgM antibodies against hepatitis A virus in your blood, which can indicate an active infection with the hepatitis A virus.

Quick summary

["IgM antibodies may appear shortly after infection and help confirm recent hepatitis A exposure."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
63681-1
Short code
Drug use hepatitis SSAGA II
Synonyms
Drug use hepatitis SSAGA II
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ssaga-ii
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

What Does This Test Measure?

The test looks for IgM antibodies specific to hepatitis A virus in your serum. IgM antibodies are part of your immune response and typically develop within a few weeks after infection. This test helps determine if you’ve recently been infected with the hepatitis A virus.

Why Might You Need This Test?

Your healthcare provider may order this test if you have symptoms like fever, fatigue, nausea, jaundice (yellowing of skin/eyes), or abdominal pain, especially if you’ve recently traveled to areas with higher hepatitis A risk or had close contact with someone who has the virus.

What Are Common Symptoms?

Hepatitis A infection often starts with flu-like symptoms, including fatigue, loss of appetite, nausea, and abdominal discomfort. Later, you may develop jaundice (yellowing of skin/eyes), dark urine, or light-colored stools. However, some people may not have any symptoms at all.

How Is This Test Performed?

A blood sample is taken from a vein in your arm. The sample is sent to a lab where it’s tested for IgM antibodies using an immunoassay method, which detects the presence of these antibodies in your serum.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

IgM Hepatitis A Antibody

Frequently asked questions

How long do IgM antibodies stay in the blood?
IgM antibodies to hepatitis A typically appear within 2 to 6 weeks after infection and can remain detectable for several months. If your IgM test is positive, it suggests an active infection, but it won’t provide information about past immunity.
Can this test tell me if I’ve had hepatitis A before?
No, this test only detects IgM antibodies, which indicate recent infection. To determine past immunity or exposure, your provider may also check for IgG antibodies or hepatitis A virus RNA (if available).
What does a positive result mean?
A positive IgM result means you likely have an active hepatitis A infection and should seek medical advice for treatment and management. A negative result does not rule out infection if tested too early or does not indicate immunity.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy