Immunoglobulin A (IgA) in serum/plasma by nephelometry
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.
["IgA helps defend your immune system and may be checked if you have recurring infections or certain immune-related conditions."]
Key facts at a glance
- LOINC
- 74865-7
- Short code
- IgA lamba SerPl-mCnc
- Synonyms
- IgA lamba SerPl-mCnc
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- 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 Does This Test Measure?
IgA is one of the key proteins in your immune system. It’s found in high concentrations in bodily fluids like saliva, tears, and mucus, but it’s also present in your blood. This test specifically looks at the concentration of IgA in your serum or plasma, which can help doctors understand how well your immune system is functioning to fight infections.
Why Might You Need This Test?
Doctors may order an IgA test if you have symptoms like frequent infections, digestive issues, or if you’re being evaluated for conditions like common variable immunodeficiency (CVID), certain autoimmune diseases, or after receiving certain treatments that affect the immune system.
What to Expect Before the Test
No special preparation is usually needed for this test. You may have a small needle inserted into your arm to draw blood. If you’re taking blood from a vein in your arm, you might feel a slight pinch or pressure, but it’s generally quick and not painful. If you’re concerned about needles, let your healthcare provider know.
What to Expect During the Test
The blood sample is collected and sent to a lab where it’s analyzed using a method called nephelometry. This technique measures how much light scatters when it interacts with IgA particles in the blood. The results help determine your IgA levels.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Low IgA levels may indicate a weakened immune response, increasing your risk of infections. High IgA levels can sometimes be linked to certain autoimmune conditions or allergic reactions. Your doctor will use these results along with your medical history and symptoms to guide diagnosis and treatment.
Short name
IgA Level
Frequently asked questions
Why might my IgA levels be checked if I have frequent infections?
What could cause my IgA levels to be higher than normal?
Is there anything I should avoid before this test?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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.
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