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Total T-Cell Count (with Subtype Differentiation: Naive, Central Memory, Effector Memory)

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

This test measures different types of T-cells in your blood, which help your immune system fight infections and diseases. It provides insight into your immune cell balance.

Quick summary

["Understanding your T-cell subtypes can help identify immune function or deficiencies."]

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

Key facts at a glance

LOINC
56900-4
Short code
TdT Cells NFr CSF FC
Synonyms
TdT Cells NFr CSF FC
Category
chemistry
Sample
csf
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
flow-cytometry
Specimen volume
1-2 mL
Stability
Immediate analysis required, Refrigerated: 1h
Hemolysis max
200
TAT
4–24 hours
Order
routine

Why This Test Might Be Ordered

Your healthcare provider may recommend this test if you have symptoms of immune disorders, such as frequent infections, unexplained fatigue, or autoimmune conditions. It could also be used to monitor treatment responses in certain immune-related illnesses or before/after organ transplants.

What to Expect Before the Test

No special preparation is needed. You may have a blood draw at a clinic or lab. If you’re on blood thinners, let your provider know before the test.

What the Results Mean

Results show proportions of different T-cell types (naive, central memory, effector memory). Abnormal counts may indicate immune system issues, such as low immune response or overactive inflammation. Your provider will interpret results in the context of your health history.

Common Conditions Linked to T-Cell Results

Changes in T-cell counts can signal conditions like HIV/AIDS (where naive T-cells drop), autoimmune diseases (e.g., rheumatoid arthritis), or immune deficiencies (e.g., severe combined immunodeficiency). High or low counts may also reflect aging or chronic illnesses.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical significance paragraph: Elevated or reduced T-cell subsets can signal immune dysfunction, chronic infections, or underlying diseases. This test helps guide treatment decisions for immune-related disorders.

Short name

T-cell subset analysis (serum/plasma)

Frequently asked questions

What does a ‘normal’ result mean for me?
A ‘normal’ result doesn’t mean your immune system is perfectly balanced—it simply means your T-cell proportions fall within general reference ranges. Your provider will assess results alongside your symptoms and medical history.
Can I get this test at home?
No, this test requires a blood sample collected by a healthcare professional in a clinical setting.
How often should I get this test?
Frequency depends on your health condition and provider’s recommendations. Some patients get it yearly or as needed for monitoring.
  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