Skip to content

Immunoglobulin A (IgA) in Serum or Plasma

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 bacteria and viruses.

Quick summary

["IgA helps defend against common infections and plays a role in immune function."]

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

Key facts at a glance

LOINC
44583-3
Short code
IgA Ab SerPl Ql HAI
Synonyms
IgA Ab SerPl Ql HAI
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
1.5
Ref high
9
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
hai
CPT
83002
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 This Test Measure?

IgA is one of the main antibodies your immune system produces. It’s found in high concentrations in bodily fluids like saliva, tears, and mucus, but it’s also present in blood plasma. Low levels may suggest immune system issues or certain medical conditions.

Why Might You Need This Test?

Doctors may order an IgA test to diagnose or monitor conditions like immune deficiencies, certain autoimmune diseases, or to check for infections where IgA antibodies are important. It can also be part of a broader evaluation for digestive or respiratory health.

How Is the Test Done?

A blood sample is taken from a vein in your arm. The blood is then processed to measure IgA levels using a specialized immunoassay method. Results are compared to general reference ranges for healthy adults.

What Do the Results Mean?

Results may be below, at, or above normal reference ranges. Low IgA levels might indicate weakened immune function, while high levels could be due to certain medical treatments or conditions. Your doctor will interpret results in the context of your health history.

Reference range

Follicular: 1.5-9.0 mIU/mLN/A

Specimen: serum

For females: inform if menstrual cycle status. For certain tests, timing within menstrual cycle may matter.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

IgA Level

Frequently asked questions

What causes low IgA levels?
Low IgA levels can result from genetic immune deficiencies, certain autoimmune diseases, long-term infections, or conditions like celiac disease. It may also appear in people with weakened immune systems due to treatments like chemotherapy.
What causes high IgA levels?
High IgA levels can be linked to chronic infections, certain autoimmune conditions, or as a side effect of medications. Some people with long-term inflammatory diseases may also have elevated IgA.
Can IgA levels change over time?
Yes, IgA levels can fluctuate due to infections, immune responses, or medical treatments. Repeated testing may be needed if your doctor suspects a condition affecting IgA production or function.
  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