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Lymphocyte Subset Immunophenotyping by Flow Cytometry (with Probe for Specific Markers)

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

This test measures specific types of white blood cells called lymphocytes in your blood, focusing on their unique surface markers to help assess immune function.

Quick summary

["Understanding your immune cell types can help diagnose or monitor conditions affecting your immune system."]

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

Key facts at a glance

LOINC
65761-9
Short code
Lymph subset interp Bld FC-Imp
Synonyms
Lymph subset interp Bld FC-Imp
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 Is Done

Doctors may order this test to evaluate immune health, especially if you have symptoms like frequent infections, unexplained fatigue, or signs of immune system disorders. It can also be used before or after treatments that affect the immune system, such as chemotherapy or certain medications.

What to Expect Before the Test

No special preparation is needed. You’ll have a small needle inserted into a vein (usually in your arm) to draw blood. The process takes about 5 minutes, and you may feel a brief pinch or discomfort.

What the Test Results Mean

The test identifies different lymphocyte subsets (e.g., T cells, B cells, natural killer cells) by detecting specific proteins (markers) on their surfaces. Abnormal counts or ratios may indicate conditions like immunodeficiency, autoimmune diseases, or cancers of the blood.

Common Conditions Monitored

This test helps diagnose or track conditions such as HIV/AIDS, leukemia, lymphoma, or other immune-related disorders. It may also be used to check immune responses after organ transplants or before/after cancer treatments.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Lymphocyte Subset Analysis

Frequently asked questions

What does a ‘lymphocyte subset profile’ tell me about my health?
It provides detailed information about the types and proportions of your immune cells, helping identify whether your immune system is functioning normally or if there’s an imbalance that may require further medical evaluation.
How long will it take to get my results?
Results are typically available within 1–3 business days, depending on lab processing times. Your doctor will discuss them with you during your follow-up visit.
Can I eat or drink before this test?
No special diet is needed. You can eat and drink normally, but avoid alcohol for 24 hours before the blood draw if your doctor recommends it.
  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