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CD3+ T Lymphocyte Count (Absolute)

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

This test measures the number of CD3+ T lymphocytes in your blood, which are a key type of white blood cell involved in immune responses.

Quick summary

["CD3 T cells help fight infections and regulate immune activity."]

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

Key facts at a glance

LOINC
107037-4
Short code
CD3LYM
Synonyms
CD3 Cells/lymph NFr Spec FC
Category
chemistry
Sample
serum
Container
EDTA (lavender-top) or ACD (yellow-top) anticoagulant tube for whole blood flow cytometry. Sodium heparin (green-top) tubes are also acceptable. Specimen must remain at room temperature and be processed within specified stability limits.
Units
N/A
Ref low
60
Ref high
85
Critical range
10 N/A – 95 N/A
Fasting
false
Population
adult
Sex
all
Age range
≥ 0 years
Method
flow-cytometry
CPT
86359
SNOMED
27058007
Specimen volume
Minimum 3-5 mL whole blood for adults; 1-2 mL for pediatric patients. Adequate sample is required for cell counting, viability assessment, and antibody staining panels.
Stability
Whole blood must be processed within 24-30 hours of collection when stored at room temperature (18-25°C). Do not refrigerate or freeze whole blood as this compromises cell viability and surface marker integrity. Prolonged storage leads to loss of antigen expression and inaccurate subset enumeration.
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

What Does This Test Measure?

CD3+ T lymphocytes are a subset of white blood cells that play a central role in your immune system. They help your body recognize and respond to foreign invaders like bacteria and viruses, as well as regulate immune reactions to prevent overactivity.

Why Might You Need This Test?

Doctors may order this test to evaluate immune function, diagnose or monitor conditions like immunodeficiency, autoimmune diseases, or certain cancers (e.g., lymphoma, leukemia). It can also help assess how well your immune system is responding to treatments.

How Is the Test Performed?

A blood sample is drawn from a vein, usually in your arm. The sample is then analyzed in a lab to count the number of CD3+ T cells present in your bloodstream.

What Are Common Uses?

This test is often used in conjunction with other blood tests to diagnose or monitor conditions affecting the immune system, such as HIV/AIDS, certain cancers, or chronic infections.

Reference range

CD3+ T cells: 60-85% of total lymphocytes; Absolute CD3 count: 800-2500 cells/µL (adult reference values vary by laboratory). Pediatric values are age-dependent with higher absolute counts in young children that gradually decline to adult levels by adolescence.N/A

Specimen: serum

No special patient preparation is required. However, patients should be informed that certain medications (corticosteroids, immunosuppressants, chemotherapy agents, and biologic therapies) can significantly alter T-cell subset counts and should be documented. Recent vaccinations may transiently affect lymphocyte populations.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CD3 Lymphocyte Count

Frequently asked questions

What does a low CD3 lymphocyte count mean?
A low CD3 count may suggest an immune deficiency, such as a congenital disorder, severe infection, or certain medications that suppress the immune system. It could also be seen in conditions like HIV/AIDS or certain cancers. Your doctor will consider your full medical picture to determine the cause.
How long does it take to get results from this test?
Results from this test are typically available within 1 to 3 business days, depending on your lab’s processing schedule. Your healthcare provider will discuss the results with you during your follow-up visit.
Can lifestyle changes affect CD3 lymphocyte counts?
While diet, stress, and exercise can influence overall immune function, they generally do not directly alter CD3 lymphocyte counts. However, chronic illnesses or infections may temporarily affect immune cell counts. Always follow your doctor’s advice regarding lifestyle modifications related to your specific condition.
  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