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Fluorescent Antibody Titration for Viral Antigen (e.g., Influenza Virus)

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

This test measures the amount of a specific viral protein in your blood or serum using a fluorescent antibody technique. It helps determine if you have an active infection with certain viruses, such as influenza.

Quick summary

["Assists in diagnosing active viral infections by detecting viral antigens in your blood or serum."]

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

Key facts at a glance

LOINC
24289-1
Short code
FLUAV Ab sp1 Titr Ser
Synonyms
FLUAV Ab sp1 Titr Ser
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

How the Test Works

Your sample is mixed with fluorescent-labeled antibodies that bind specifically to the virus’s proteins. If the virus is present, these antibodies attach, and a fluorescent signal is generated. The strength of this signal is measured to determine the viral antigen concentration.

What to Expect Before the Test

No special preparation is needed. You may have a blood draw (serum/plasma) or other fluid sample collected, depending on the clinical indication. Avoid alcohol or certain medications for 24 hours before testing if instructed by your provider.

Common Uses

This test is used primarily to diagnose active viral infections, such as influenza, in patients with symptoms like fever, cough, or respiratory distress. It can also guide treatment decisions or monitor viral load in certain clinical settings.

Potential Results and Interpretation

Results are qualitative (positive/negative) or quantitative (titer values), indicating the presence and relative amount of viral antigen. A positive result suggests active infection, while a negative result means no detectable antigen is present.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Influenza Viral Antigen Titration

Frequently asked questions

Why might my doctor order this test?
Your doctor may recommend this test if you have symptoms of a viral infection, such as flu-like illness, or if you are at high risk for certain viral infections. It may also be used in research or outbreak investigations.
What does a positive result mean?
A positive result indicates the presence of the viral antigen in your sample, suggesting an active infection. Your doctor will discuss further steps, such as treatment options or additional testing.
How long will it take to get my results?
Results are typically available within 24 to 48 hours, depending on lab processing times and testing volume. Your healthcare provider will contact you with the final result once it is ready.
  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