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Serum/plasma mass concentration of CD45-positive lymphocytes (absolute count)

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

This test measures the number of a specific type of white blood cell called CD45+ lymphocytes in your blood. CD45 is a protein found on most white blood cells, helping identify their presence and activity.

Quick summary

["CD45+ lymphocyte counts help assess immune health and detect conditions affecting white blood cells."]

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

Key facts at a glance

LOINC
69038-8
Short code
LPT PHA max/CD45 NFr Bld FC
Synonyms
LPT PHA max/CD45 NFr Bld FC
Category
chemistry
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Ref low
0.8
Ref high
1.2
Critical range
— – 5 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
flow-cytometry
CPT
85610
SNOMED
396252006
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

What Is CD45+ Lymphocyte Count Used For?

Doctors use this test primarily to evaluate immune function, especially in diagnosing and monitoring conditions like infections, blood disorders, or immune deficiencies. It may also help assess responses to treatments that affect white blood cell counts.

How Is the Test Performed?

A small blood sample is drawn from your arm. The blood is processed to separate the white blood cells, and the test measures the concentration of CD45+ cells using a specialized laboratory technique.

Preparation for the Test

No special preparation is needed for this test. You may eat and drink normally before your appointment. If you’re on blood-thinning medications, let your healthcare provider know before the test.

What Are Possible Results?

Results are expressed as a count of CD45+ lymphocytes per microliter (µL) of blood. While reference ranges vary by lab, lower than expected counts may suggest immune suppression or certain blood disorders, while higher counts could indicate inflammation or other conditions.

Reference range

INR: 0.8-1.2 (warfarin: 2.0-3.0)N/A

Specimen: whole-blood

Inform your healthcare provider if you are taking blood thinners. No special preparation required.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CD45+ Lymphocyte Count

Frequently asked questions

Why might my doctor order this test?
Your doctor may recommend this test if you have symptoms like frequent infections, unexplained fatigue, or if you’re undergoing treatment that could affect your immune cells. It may also be part of routine monitoring for conditions like HIV or blood cancers.
What does a low CD45+ lymphocyte count mean?
A low count may indicate an immune deficiency, where your body struggles to fight infections effectively. This could be due to genetic disorders, certain medications, or chronic illnesses. Your doctor will discuss next steps based on your overall health and symptoms.
Can diet or lifestyle affect CD45+ lymphocyte counts?
While diet and lifestyle can influence overall immune health, they typically don’t directly impact CD45+ lymphocyte counts in the same way as certain medications or medical conditions. Focus on a balanced diet and avoid excessive stress to support general immune function.
  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