Hepatitis A Virus Antibody, IgM (Serum) – Reverse Passive Hemagglutination Test
This test detects IgM antibodies to the hepatitis A virus in your blood, which can help identify recent infection.
["Recent hepatitis A exposure may be suspected if this antibody is present."]
Key facts at a glance
- LOINC
- 29482-7
- Short code
- Hep v A-wave reversal.max exp DOP
- Synonyms
- Hep v A-wave reversal.max exp DOP
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- us-doppler
- 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 This Test Measures
The test looks for IgM antibodies specific to the hepatitis A virus. IgM antibodies are typically produced shortly after infection and can indicate an acute (recent) hepatitis A virus infection. This method uses reverse passive hemagglutination to detect these antibodies in serum.
Why It’s Ordered
Your healthcare provider may order this test if you have symptoms like fever, fatigue, nausea, or jaundice, or if you’ve recently traveled to areas with higher hepatitis A risk. It may also be used to confirm exposure in individuals with known risk factors.
Sample Collection and Preparation
A blood sample is drawn from a vein, usually in your arm. The serum portion is separated and tested for IgM antibodies using a specialized laboratory technique.
What to Expect Before the Test
No special preparation is needed. You may eat and drink normally, but inform your provider if you’re on any medications that could affect blood tests.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Positive IgM results suggest recent hepatitis A infection and may prompt further evaluation or vaccination guidance. Negative results do not rule out infection if tested too early or if the test was not properly interpreted. This test is not used for monitoring chronic infection or vaccination status.
Short name
IgM Hepatitis A Antibody (Reverse PAH)
Frequently asked questions
When might I get this test?
What does a positive result mean?
Can I get this test at home?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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.
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