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Plasma CD4 Cell Count

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

This test measures the number of CD4 cells (a type of white blood cell) in your plasma. CD4 cells help your immune system fight infections.

Quick summary

["CD4 cells are crucial for immune function; lower counts may indicate weakened immunity."]

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

Key facts at a glance

LOINC
93317-6
Short code
Plt CD42a Act/Nor Bld FC
Synonyms
Plt CD42a Act/Nor Bld FC
Category
hematology
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 CD4 Count Used For?

CD4 counts are primarily used to monitor immune health, especially in people with HIV or other immune-related conditions. They help doctors track how well your immune system is functioning and guide treatment decisions.

How Is This Test Performed?

A small blood sample is drawn from a vein in your arm. The blood is processed to count the CD4 cells, which are then analyzed using a specialized blood test.

Why Might You Need This Test?

You may need a CD4 count if you have HIV, an autoimmune disorder, or another condition affecting your immune system. Doctors also use it to check how your immune system responds to treatments.

What Do Results Mean?

Results show the number of CD4 cells per microliter of blood. While specific ranges vary by lab, lower counts may signal immune suppression, while higher counts suggest a stronger immune response.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CD4 T-Cell Count

Frequently asked questions

How often should I expect this test?
The frequency depends on your medical condition. For HIV patients, tests may be done monthly or as recommended by your healthcare provider. Others with immune-related conditions may need testing less often.
What are typical reference ranges?
Typical reference ranges for CD4 counts vary by lab and age. Generally, healthy adults have counts between 500–1,500 cells per microliter. Your doctor will interpret results based on your specific needs.
Can I do anything to prepare for this test?
No special preparation is needed. However, avoid heavy exercise or alcohol before the test, as it may affect blood test 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