Skip to content

CD45-Positive Cell Count Ratio, Whole Blood — Flow Cytometry

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

A flow cytometry test that measures the proportion of blood cells carrying the CD45 marker, which is present on most white blood cells.

Quick summary

["This test helps evaluate the relative presence of CD45-positive white blood cells in a blood sample."]

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

Key facts at a glance

LOINC
88053-4
Short code
Cell.DNT-CD45R+TCRa b # Bld FC
Synonyms
Cell.DNT-CD45R+TCRa b # Bld FC
Category
liver
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

What is this test?

This test measures the ratio or proportion of blood cells that express CD45, a cell-surface protein found on most white blood cells. It is performed using flow cytometry and may provide information about the makeup of the circulating blood cells.

Why might I need this test?

It may be ordered to investigate an unusual blood count, unexplained changes in white blood cells, or suspected immune-cell disorders. It is generally interpreted with other laboratory tests and the results of a physical examination.

How is the test performed?

A blood sample is collected, usually by a vein. The laboratory adds fluorescent-tagged antibodies to the cells and uses flow cytometry to determine how many cells carry the CD45 marker.

How do I prepare for the test?

No special preparation is usually required, and fasting is generally not necessary. Follow the laboratory's instructions and tell the healthcare provider if you have recently had a blood transfusion, infection, or surgery.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CD45 cell ratio

Frequently asked questions

What does a CD45-positive cell mean?
It means that the blood cell has the CD45 protein on its surface. CD45 is found on most white blood cells but generally not on red blood cells or platelets.
Does this test identify a specific disease?
No. The result is one part of the evaluation and usually must be considered alongside other blood tests, symptoms, and medical history.
Is fasting required for this test?
Fasting is usually not required. Follow any preparation instructions provided by the ordering clinician or laboratory.
  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