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Fluorescent Antibody Assay for Viral Antibodies (Serum/Plasma)

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

This test detects antibodies in your blood that may indicate past or current exposure to a flu virus. It helps determine if you’ve been infected by a specific type of influenza virus.

Quick summary

["This test helps doctors track flu exposure and guide treatment decisions."]

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

Key facts at a glance

LOINC
44565-0
Short code
FLUAV+FLUBV Ab Ser Ql
Synonyms
FLUAV+FLUBV Ab Ser Ql
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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 uses a fluorescent immunoassay (FIA) to identify antibodies produced by your immune system in response to flu viruses. Antibodies are proteins your body makes to fight infections. This test checks for specific antibodies linked to different flu strains, such as influenza A or B.

Why It’s Done

Doctors may order this test if you have symptoms of the flu (e.g., fever, cough, fatigue) or if you’ve been exposed to someone with the flu. It can also help confirm a diagnosis when other tests are inconclusive or if you’re unsure about the cause of your symptoms.

Sample Collection and Preparation

A blood sample is taken from a vein in your arm. The blood is processed to separate serum or plasma, which is then tested for flu-specific antibodies. The test does not measure the virus itself but rather your immune response to it.

What to Expect Before the Test

No special preparation is needed. You may have some mild discomfort from the needle, but it usually goes away quickly. If you’re on blood-thinning medication, let your doctor know before the test.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Viral Antibody Screening (FIA)

Frequently asked questions

What Does a Positive Test Mean?
A positive test means your body has produced antibodies against the flu virus, confirming exposure. This does not necessarily mean you were sick at the time of testing, as antibodies can take days to develop after infection.
Can This Test Detect All Types of Flu?
This test can detect antibodies against common flu strains (influenza A and B), but it may not catch all possible variants. If symptoms persist or worsen, further testing (like PCR) may be needed for a definitive diagnosis.
How Long Does It Take to Get Results?
Results are typically available within 24 to 48 hours, depending on lab processing times. Follow-up with your doctor if you have questions about your results.
  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