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Influenza Virus Nucleoprotein Antibody, Rapid Immunoassay (Serum/Plasma)

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

This test detects antibodies to the influenza virus, helping identify if your body has been exposed to the flu virus.

Quick summary

["Checks for past flu exposure via antibody presence in a quick lab test."]

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

Key facts at a glance

LOINC
72366-8
Short code
FLUAV + FLUBV Ag Nose IA.rapid
Synonyms
FLUAV + FLUBV Ag Nose IA.rapid
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ia-rapid
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 measures the presence of antibodies against the nucleoprotein of influenza viruses. Antibodies are proteins your immune system produces in response to infection. If you have these antibodies, it suggests you may have been previously exposed to the flu virus.

How the Test Works

This is a rapid immunoassay (IA) test performed on serum or plasma. It detects specific antibodies (immunoglobulins) that target the influenza virus’s nucleoprotein. The result is typically available within minutes.

Why It’s Done

Doctors may order this test to confirm past exposure to the flu, especially if symptoms were present but testing for active infection (like PCR or rapid antigen tests) was negative. It can also be used in research or epidemiological studies.

Sample Collection and Preparation

A blood sample is drawn from your arm, and the serum or plasma is separated from blood cells. This sample is then tested immediately or sent to a lab for rapid immunoassay analysis.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Positive results indicate prior exposure to influenza viruses, meaning your immune system has likely developed immunity. This can be useful for monitoring immunity in high-risk populations, vaccine effectiveness studies, or diagnosing past infections when active viral detection is inconclusive.

Short name

Influenza Antibody Screen (Rapid Test)

Frequently asked questions

What does a positive result mean?
A positive result means your body has produced antibodies against the influenza virus, suggesting you were previously infected. This does not indicate whether you currently have the flu or if the infection was recent.
What does a negative result mean?
A negative result means your blood sample did not detect antibodies against the influenza virus at this time. This could mean you have never been exposed, or if you were, the antibodies may not have developed yet or have cleared from your system.
Can this test be used to diagnose the current flu?
No, this test is not for diagnosing an active flu infection. It only detects past exposure. For current flu symptoms, you would need a rapid antigen test or PCR test instead.
  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