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Immunoglobulin A (IgA) in Serum

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

This test measures the amount of Immunoglobulin A (IgA), a type of antibody in your blood serum. IgA helps protect your body from infections by preventing harmful substances from entering tissues.

Quick summary

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

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

Key facts at a glance

LOINC
56539-0
Short code
IF Ab Ser IA-aCnc
Synonyms
IF Ab Ser IA-aCnc
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
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 Is Immunoglobulin A (IgA)?

IgA is a key part of your immune system, found in high concentrations in mucous membranes (like those in your nose, throat, and digestive tract). It plays a role in preventing pathogens from entering your body and can also be detected in other bodily fluids. IgA levels can vary based on health, immune status, and certain medical conditions.

Why Might You Need This Test?

Doctors may order an IgA test to evaluate immune function, diagnose conditions like immunodeficiency, or assess symptoms such as frequent infections, chronic inflammation, or autoimmune disorders. It can also help monitor certain diseases, like celiac disease or inflammatory bowel disease.

Common Reasons for Testing

Common reasons include unexplained infections, recurrent sinus or respiratory issues, or symptoms linked to immune system dysfunction. It may also be part of a broader evaluation for conditions affecting the immune system or gastrointestinal health.

Sample Collection and Preparation

A blood sample is typically drawn from a vein in your arm. The blood is processed to separate serum, which is then tested for IgA levels. This test does not require fasting and is usually done in a lab setting.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

IgA Levels and Their Clinical Significance

Short name

IgA Level

Frequently asked questions

How long does it take to get results from this test?
Results are usually available within 1–3 business days, depending on your lab’s processing schedule. Your healthcare provider will discuss the findings with you during your follow-up visit.
Can IgA levels change with age or pregnancy?
Yes, IgA levels can fluctuate with age, immune health, and certain medical conditions. Pregnancy may also influence IgA production, but your doctor will interpret results in the context of your overall health.
What does it mean if my IgA level is low?
Low IgA levels may indicate a weakened immune response, increasing susceptibility to infections. Conditions like selective IgA deficiency or autoimmune disorders could be considered, but further testing and evaluation by a healthcare provider are needed.
  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