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Lymphocyte Differential (Blood) with Immunophenotyping by Flow Cytometry

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

This test measures the types and proportions of white blood cells called lymphocytes in your blood, along with identifying specific cell markers to help diagnose conditions like infections, immune disorders, or cancers.

Quick summary

["Understanding your lymphocyte cell types can help guide treatment for immune or blood-related health concerns."]

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

Key facts at a glance

LOINC
101119-6
Short code
Leuk and lymphma immnphntypng Spec
Synonyms
Leuk and lymphma immnphntypng Spec
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
flow-cytometry
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

Why This Test Is Done

Your doctor may order this test to evaluate your immune system, check for infections, or diagnose conditions such as leukemia, lymphoma, or autoimmune diseases. It can also help monitor treatment responses or detect hidden blood disorders.

What to Expect Before the Test

No special preparation is needed. You’ll have a small needle inserted into your arm or hand to draw blood. If you’re nervous, let your healthcare provider know—they can help make it more comfortable.

What the Results Mean

The test looks at different types of lymphocytes (e.g., T-cells, B-cells, natural killer cells) and their markers. Abnormal counts or patterns may signal immune dysfunction, cancer, or other health issues. Your doctor will interpret results in the context of your overall health.

Common Conditions Affecting Results

Changes in lymphocyte counts or types can occur with infections (like COVID-19 or HIV), chronic illnesses (such as lupus or rheumatoid arthritis), or cancers (like lymphoma or leukemia). Some medications or treatments may also alter these cells.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Lymphocyte Profile

Frequently asked questions

Will I need to fast before this test?
No fasting is required. This test is typically done on an empty stomach for some blood tests, but lymphocyte counts are not affected by food. If you’re unsure, ask your doctor.
How long will it take to get my results?
Results are usually available within 1–3 business days, depending on your lab. Your doctor will discuss them with you during your follow-up visit.
Can I eat or drink anything before this test?
You can eat and drink normally before this test. Since it’s a blood draw, hydration is fine, but avoid excessive caffeine or alcohol if your doctor has specific instructions.
  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