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Absolute Count of CD3+ Lymphocytes (Peripheral Blood)

Published: August 9, 2026Updated: August 15, 2026

This test measures the number of CD3+ cells, a type of white blood cell important for immune function. CD3 cells are part of T lymphocytes, which help fight infections and regulate the immune response.

Quick summary

["CD3+ lymphocytes help your immune system defend against infections and maintain balance in your body."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 15, 2026Editorial policy

Key facts at a glance

LOINC
90304-7
Short code
CD3LYMPH
Synonyms
CD3 Cells/lymph NFr Bld
Category
chemistry
Sample
whole-blood
Container
EDTA (lavender/purple-top) vacutainer tube; alternatively, sodium heparin (green-top) tube for flow cytometry applications. ACD tubes are also acceptable.
Units
N/A
Ref low
60
Ref high
85
Critical range
200 N/A – —
Fasting
false
Population
adult
Sex
all
Age range
0–120 years
Method
Flow cytometry using fluorescently labeled monoclonal antibodies against CD3 surface antigen; whole blood is stained, lysed, washed, and analyzed on a flow cytometer with calculation of CD3+ T-lymphocytes as an absolute count and percentage of total lymphocytes.
CPT
86359
SNOMED
115006001
Specimen volume
3-5 mL whole blood for adults; 1-2 mL minimum for pediatric patients. Minimum 0.5 mL whole blood required for analysis.
Stability
Specimen should be processed within 24-30 hours of collection when stored at room temperature (18-25°C). Refrigeration (2-8°C) may extend stability to 48 hours but is generally not recommended as it may affect cell viability and surface antigen expression. Do not freeze.
Hemolysis max
100
Lipemia max
500
Icterus max
50
TAT
4–24 hours
Order
routine

Why This Test Is Done

Doctors may order this test to evaluate immune function, assess immune-related conditions (such as certain cancers, autoimmune diseases, or HIV), or monitor treatment responses in patients with weakened immune systems. It can also help diagnose or monitor conditions affecting T cells.

What to Expect Before the Test

No special preparation is needed. You may have a small needle inserted into a vein in your arm to draw blood. Tell your doctor if you have any concerns or allergies to blood collection procedures.

What the Results Mean

Results are typically reported as the absolute count of CD3+ cells per microliter (cells/µL) of blood. Lower than expected counts may indicate immune deficiencies, while higher counts could be due to certain infections or overactive immune responses.

Common Conditions Monitored

This test is often used in patients with HIV/AIDS, lymphoma, leukemia, or other immune system disorders. It helps track how well treatments are working and whether the immune system is recovering or deteriorating.

Reference range

CD3+ T-lymphocytes typically constitute 60-85% of total lymphocytes in healthy adults. Absolute CD3 count: approximately 800-3000 cells/μL (0.8-3.0 x 10^9/L). Pediatric values are higher at birth and decline gradually to adult levels by approximately 6-8 years of age.N/A

Specimen: whole-blood

No fasting required. Patients should be well-hydrated. Recent corticosteroid therapy, chemotherapy, immunosuppressive drugs, radiation therapy, or active infection may significantly alter CD3 counts and should be documented. Stress, exercise, and circadian variation may mildly affect lymphocyte subset distributions; morning collections are preferred when possible.

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 lymphocyte count may suggest an impaired immune response, potentially due to conditions like HIV/AIDS, certain cancers (e.g., lymphoma), or autoimmune diseases. It can also occur in people undergoing chemotherapy or radiation therapy for cancer.
What does a high CD3 lymphocyte count mean?
A high CD3 lymphocyte count might indicate an overactive immune response, such as in certain infections (e.g., viral infections), chronic inflammatory conditions, or some autoimmune disorders. It can also be seen in people with certain types of leukemia or lymphoma.
How often should I get this test?
The frequency of this test depends on your medical condition and treatment plan. Your doctor will determine how often you need it based on your specific needs, such as monitoring immune function in HIV patients, cancer treatment progress, or autoimmune disease management.
  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 15, 2026. · Read our editorial policy