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T-cell subset count in peripheral blood (absolute count)

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

This test measures the number of T-cells, a type of white blood cell important for immune function, in your blood.

Quick summary

["Your immune system relies on T-cells to fight infections and maintain health."]

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

Key facts at a glance

LOINC
52996-6
Short code
TdT Cells NFr Bld FC
Synonyms
TdT Cells NFr Bld FC
Category
chemistry
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
flow-cytometry
Specimen volume
3 mL
Stability
Room temperature: 4h, Refrigerated: 24h
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

Why This Test Might Be Ordered

Doctors may order this test to check for immune system issues, monitor treatment responses (e.g., for cancer or autoimmune conditions), or evaluate symptoms like frequent infections, fatigue, or unexplained weight loss.

What to Expect Before the Test

No special preparation is needed. You’ll have a small needle inserted into your arm or hand to draw blood. It usually takes a few minutes, and you may feel a brief pinch.

What the Results Mean

Results show the total number of T-cells in your blood. Low counts may indicate immune deficiencies, while high counts could suggest overactive immune responses or other conditions. Your doctor will interpret results in the context of your health history.

Common Conditions Affecting T-Cell Counts

T-cell counts can drop due to HIV/AIDS, certain cancers (e.g., lymphoma), autoimmune diseases, or treatments like chemotherapy. They may rise in infections, chronic inflammation, or rare genetic disorders.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

T-cell count

Frequently asked questions

Is there a normal range for this test?
No standard range applies universally. Your doctor will compare your results to your baseline or lab-specific references and consider your overall health.
What should I do if my T-cell count is low?
If your count is low, your doctor may recommend lifestyle changes (e.g., diet, stress management), treatments (e.g., medications), or further testing to identify the cause.
Can diet or supplements affect T-cell counts?
Dietary changes alone won’t alter T-cell counts, but certain supplements (e.g., vitamin D) may support immune function indirectly. Always consult your doctor before starting new supplements.
  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