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Absolute Count of CD3+ Lymphocytes in Peripheral Blood

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

This test measures the number of CD3+ cells, a type of white blood cell important for immune function, found in your blood.

Quick summary

["CD3+ lymphocytes help your immune system fight infections and recognize foreign substances."]

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

Key facts at a glance

LOINC
97594-6
Short code
CD3LR
Synonyms
CD3 Cells/lymph NFr Lower resp FC
Category
chemistry
Sample
serum
Container
Sterile, leak-proof, screw-cap container appropriate for lower respiratory specimen collection; placed on wet ice or transported under conditions specified by the performing flow cytometry laboratory. Do not use formalin or other fixatives.
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
0–99 years
Method
flow-cytometry
CPT
86359
SNOMED
395124007
Specimen volume
Minimum 5–10 mL of bronchoalveolar lavage (BAL) fluid or lower respiratory specimen as required by performing laboratory; larger volumes (≥10 mL) preferred to ensure adequate cell yield for flow cytometric analysis.
Stability
Specimen should be delivered to the flow cytometry laboratory as soon as possible after collection, ideally within 1–2 hours at room temperature. Specimen stability is limited; prolonged delays may result in cell loss, decreased viability, and altered immunophenotyping results. If processing is delayed, specimen should be refrigerated at 2–8°C and processed within 24 hours per laboratory-specific protocol.
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–48 hours
Order
routine

What Does This Test Measure?

CD3+ lymphocytes are a subset of lymphocytes (a type of white blood cell) that play a key role in adaptive immunity. This test specifically counts the cells marked by the CD3 protein, which are involved in T-cell function. The result helps assess your immune system’s ability to respond to pathogens.

Why Might You Need This Test?

Doctors may order this test to evaluate immune health, diagnose conditions like immunodeficiency, or monitor treatment responses in patients with chronic illnesses (e.g., HIV, autoimmune diseases). It can also help identify lymphoproliferative disorders or assess immune recovery post-transplant.

How Is the Test Performed?

A small blood sample is drawn from a vein, typically in your arm. The blood is processed to separate and count CD3+ cells using specialized laboratory techniques, often involving flow cytometry or similar advanced methods.

What Are Common Uses?

Results may guide decisions about immune therapy, infection risk management, or monitoring immune-related side effects from treatments like chemotherapy or biologics.

Reference range

Reference ranges vary by laboratory; results are typically reported as percentage of lymphocytes and/or absolute count of CD3+ T cells per unit volume of lower respiratory specimen. Adult reference values generally align with established institutional flow cytometry reference ranges for bronchoalveolar lavage (BAL) specimens.N/A

Specimen: serum

No fasting required. Specimen is collected via bronchoscopy with bronchoalveolar lavage (BAL) or other lower respiratory sampling technique performed by a qualified healthcare provider. Patient should follow pre-bronchoscopy instructions provided by the performing physician, which may include fasting prior to sedation.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CD3+ Lymphocyte Count

Frequently asked questions

How long will it take to get my results?
Results are usually available within 1–3 business days, depending on lab processing times. Your healthcare provider will discuss the findings with you.
What does a low or high CD3+ lymphocyte count mean?
Low counts may indicate immune deficiencies, infections, or treatments affecting lymphocyte production. High counts could suggest chronic inflammation, autoimmune disorders, or certain cancers. Your doctor will interpret results in the context of your overall health.
Do I need to prepare for this test?
No special preparation is needed, but avoid heavy meals or strenuous activity 1 hour before the draw to ensure accurate results.
  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