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IgA (Immunoglobulin A) 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 preventing bacteria and viruses from sticking to surfaces in your respiratory and digestive tracts.

Quick summary

["IgA helps fight infections and supports immune function; low levels may indicate immune disorders or increased infection risk."]

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

Key facts at a glance

LOINC
18300-4
Short code
IgA Ur Ql IFE
Synonyms
IgA Ur Ql IFE
Category
chemistry
Sample
urine
Container
Sterile urine container
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
immunofixation
CPT
82784
Specimen volume
10 mL
Stability
Room temperature: 2h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

What Does IgA Serve in the Body?

IgA is the most abundant antibody in your body and plays a key role in protecting mucous membranes, such as those in your nose, throat, and digestive system. It helps prevent harmful substances from entering your body and keeps infections at bay.

Why Might You Need This Test?

Doctors may order an IgA test to diagnose or monitor conditions like recurrent infections, certain autoimmune diseases (such as lupus or celiac disease), or immune system disorders. It can also be part of a broader evaluation for conditions affecting the immune system.

How Is the Test Performed?

A blood sample is taken from a vein in your arm. The blood is then sent to a lab for analysis. The test measures the concentration of IgA in your serum or plasma.

What Are Possible Results?

Results are typically reported as a concentration value (e.g., milligrams per deciliter, mg/dL). While specific reference ranges can vary by lab, lower or higher-than-normal levels may signal potential health concerns that need further evaluation.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Low IgA levels may suggest an immune deficiency, increased susceptibility to infections, or certain autoimmune diseases. High IgA levels can sometimes be associated with chronic infections, liver disease, or certain immune disorders. Your doctor will interpret results in the context of your overall health and symptoms.

Short name

IgA Level

Frequently asked questions

What causes low IgA levels?
Low IgA levels can result from genetic immune deficiencies, chronic illnesses (like HIV or liver disease), certain medications, or conditions that affect the immune system, such as lupus or celiac disease. It may also be found in people with frequent infections or those who have had organ transplants.
What conditions might be linked to abnormal IgA levels?
Abnormal IgA levels can be linked to conditions like recurrent sinus or respiratory infections, autoimmune diseases (such as lupus or rheumatoid arthritis), or certain gastrointestinal disorders (like celiac disease). High IgA levels may also be seen in chronic infections or liver disease.
How often should I get this test?
The frequency of IgA testing depends on your health status and symptoms. If you have an immune disorder or recurrent infections, your doctor may recommend regular monitoring. Otherwise, this test is usually done as needed for specific medical reasons.
  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