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Serum or Plasma Immunoassay for Anti-IgG Antibodies to Influenza A Virus (Hemagglutinin)

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

This test measures the level of antibodies your body produces in response to exposure to the influenza A virus. It helps assess past infection or vaccination status.

Quick summary

["This test helps determine if you’ve been exposed to the flu virus before or if your immune system has developed immunity through vaccination."]

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

Key facts at a glance

LOINC
107915-1
Short code
HLA I IgG ab SerPl IA
Synonyms
HLA I IgG ab SerPl IA
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
CPT
82784
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 detects specific antibodies (IgG) that your immune system creates after encountering the influenza A virus. These antibodies are part of your body’s immune response and can last longer than other immune markers, indicating past infection or immunity from vaccination.

Why It’s Done

Doctors may order this test to evaluate whether you’ve had prior exposure to the influenza A virus, which can inform decisions about vaccination, immune response monitoring, or diagnosing chronic infections in rare cases.

Common Uses

Commonly used in research or specialized clinical settings to study immune responses, monitor long-term immunity, or investigate unusual antibody profiles in certain conditions.

What to Expect Before the Test

No special preparation is needed. A blood sample is drawn from a vein in your arm, similar to other blood tests. You may feel a slight pinch, but it usually takes a few minutes to complete.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Influenza A Virus IgG Antibody (Serum/Plasma)

Frequently asked questions

How long does it take to develop detectable IgG antibodies after exposure to the flu?
IgG antibodies typically appear within 2–4 weeks after initial infection or vaccination. However, timing can vary depending on the strength of your immune response.
Can this test differentiate between infections caused by different strains of influenza A?
This test measures general IgG antibodies to the influenza A virus hemagglutinin protein, not specific strains. For strain-specific detection, additional tests may be needed.
Is there any risk or discomfort associated with this blood test?
The most common discomfort is a mild bruise or slight pain at the injection site, which usually resolves quickly. Rarely, there may be a small risk of fainting or infection at the site.
  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