Lymphocyte Proliferation Response to Phytohemagglutinin (PHA) Stimulation (Blood)
This test measures how your immune system’s lymphocytes (white blood cells) respond to stimulation by phytohemagglutinin (PHA), a substance that triggers cell growth. It helps assess your immune system’s ability to mount an immune response.
["This test can help identify if your immune system may not be functioning as expected."]
Key facts at a glance
- LOINC
- 59063-8
- Short code
- Lymphocyte prolif pnl Bld
- Synonyms
- Lymphocyte prolif pnl Bld
- 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 This Test Measures
PHA is a plant protein that stimulates lymphocytes to divide and multiply. The test checks how quickly and strongly your lymphocytes grow in response to PHA. A normal response suggests your immune system is active, while a weaker response might indicate immune dysfunction.
Why It’s Done
Doctors may order this test to evaluate immune function in conditions like HIV, autoimmune diseases, or after chemotherapy. It can also help monitor immune recovery post-treatment.
Sample Collection and Preparation
A small amount of blood is drawn from your arm. The sample is processed to isolate lymphocytes, which are then exposed to PHA. The test measures cell division over time, often using a technique like a cell counter or microscopy.
What to Expect Before the Test
No special preparation is needed, but inform your doctor if you’re on medications that might affect immune function, such as steroids or chemotherapy drugs.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
A reduced lymphocyte proliferation response may suggest immune suppression, such as in HIV/AIDS, certain cancers, or after organ transplants. It can also help diagnose or monitor autoimmune diseases or conditions like chronic fatigue syndrome. Normal results indicate a healthy immune response, but further testing may still be needed for diagnosis.
Short name
PHA Lymphocyte Proliferation Test
Frequently asked questions
What does a low lymphocyte proliferation response mean?
What does a normal response mean?
Can lifestyle factors affect 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