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Serum Immunoglobulin A (IgA) Level

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

This test measures the amount of Immunoglobulin A (IgA), a type of antibody in your blood. IgA helps protect your body from infections by fighting germs.

Quick summary

["IgA helps defend against common infections and supports immune function."]

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

Key facts at a glance

LOINC
22359-4
Short code
HTLV I Ab Ser Ql
Synonyms
HTLV I 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 Does IgA Serve in Your Body?

IgA is primarily found in mucous membranes (like those in your nose, throat, and digestive tract), where it helps prevent pathogens from entering your body. It also plays a role in immune responses to infections and can be detected in blood tests for diagnostic purposes.

Why Might Your Doctor Order This Test?

Your doctor may check IgA levels if you have symptoms of immune system issues, recurrent infections, or conditions like IgA deficiency, autoimmune diseases, or certain types of allergies. It can also be part of a broader immune evaluation.

Common Conditions Linked to IgA Levels

Low IgA levels may suggest an immune deficiency, while abnormal results could be linked to conditions like chronic infections, certain cancers (e.g., lymphoma), or autoimmune disorders. High levels might indicate overactive immune responses or certain infections.

What to Expect Before the Test

No special preparation is needed for this blood test. You may have a small needle inserted into your arm to draw a blood sample, similar to other routine blood tests.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

IgA levels can help diagnose or monitor conditions affecting the immune system, but they are not definitive on their own. Results are often interpreted alongside clinical findings and other tests.

Short name

IgA Blood Test

Frequently asked questions

How long does it take to get the results of this test?
Results are typically available within 1 to 3 business days, depending on your lab and insurance. Your doctor will discuss the findings with you during your follow-up visit.
Can diet or medications affect IgA levels?
Dietary changes or certain medications (like some antibiotics or immune-suppressing drugs) may indirectly influence immune function, but they do not directly alter IgA levels. Always discuss any concerns with your healthcare provider.
Is this test painful?
The blood draw is usually brief and may cause mild discomfort, similar to a routine vaccination. Most people tolerate it well, and any pain is typically short-lived.
  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