Antibody to Flu virus, Hemagglutination Inhibition (Serum/Plasma)
This test measures your immune response to the flu virus by detecting antibodies produced in response to infection or vaccination.
["Helps determine if your body has recognized and fought off the flu virus or if you’ve been exposed recently."]
Key facts at a glance
- LOINC
- 101294-7
- Short code
- FLUAV H3 RNA Throat Ql NAA+n-prb
- Synonyms
- FLUAV H3 RNA Throat Ql NAA+n-prb
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- non-probe-amp-tar
- 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 antibodies called hemagglutination inhibitors (HAI) that your immune system creates after exposure to the flu virus. These antibodies help your body identify and neutralize future infections by the same virus.
Why It’s Ordered
Your healthcare provider may order this test if you’ve recently had symptoms of the flu, have been exposed to someone with the flu, or if you’re evaluating whether a previous flu infection or vaccination has provided immunity.
How the Test Works
A small blood sample is taken from your arm. The serum or plasma is then tested to detect the presence of HAI antibodies, which bind to the flu virus’s surface proteins to prevent it from infecting cells.
What to Expect Before the Test
No special preparation is needed. You may have a slight bruise or soreness at the injection site, but this usually goes away quickly. If you’re on blood-thinning medication, let your provider know before the test.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Positive results indicate past infection or vaccination, showing your immune system has developed antibodies to the flu. Negative results suggest either no prior exposure or recent infection that hasn’t yet produced detectable antibodies. This test can help guide decisions about flu prevention, such as vaccination timing or monitoring for recurrent exposure.
Short name
Flu Antibody Test
Frequently asked questions
How long does it take to get results?
Can this test be used to diagnose the flu?
What if my results are positive but I don’t remember having the flu?
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