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Absolute Count of CD4 and CD45 Cells in Whole Blood

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

This test measures the number of two types of white blood cells (leukocytes) in your blood: CD4 cells and CD45 cells. These cells play key roles in your immune system.

Quick summary

["Helps assess immune function and monitor conditions affecting white blood cells."]

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

Key facts at a glance

LOINC
97600-1
Short code
CD45LRC
Synonyms
CD45 Cells # Lower resp FC
Category
chemistry
Sample
serum
Container
Sterile, leak-proof container suitable for flow cytometry; polypropylene tube preferred. Use balanced salt solution or RPMI transport medium if specimen cannot be processed immediately.
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
0–120 years
Method
flow-cytometry
CPT
88184
SNOMED
444070001
Specimen volume
Minimum 2-5 mL of lower respiratory specimen (BAL fluid, bronchial washings, or brushings in transport medium). Larger volumes preferred for adequate cell yield.
Stability
Specimen should be processed within 1-4 hours of collection for optimal viability. If delayed, store at 2-8°C (refrigerated) and process within 24 hours. Do not freeze. Viability decreases significantly after 24 hours.
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

Why This Test Might Be Ordered

Your healthcare provider may recommend this test if you have symptoms of immune disorders, infections, or conditions like leukemia, lymphoma, or other blood-related diseases. It could also be used to monitor treatment progress or check for immune system changes.

What to Expect Before the Test

No special preparation is needed. You’ll have a simple blood draw, usually from a vein in your arm. The process is quick and typically painless. If you’re on blood thinners, let your provider know before the test.

What the Test Results Mean

Results show the absolute counts of CD4 and CD45 cells. While specific reference ranges vary by lab, lower-than-expected counts may indicate immune suppression, infections, or certain cancers. High counts might suggest overactive immune responses or other conditions.

Common Conditions Affecting Results

Abnormal results can be linked to immune deficiencies (e.g., HIV/AIDS), blood disorders (e.g., leukemia), or inflammatory conditions. Chronic illnesses like diabetes or kidney disease may also influence white blood cell counts.

Reference range

Reference ranges are not well established for CD45+ lymphocytes in lower respiratory specimens by flow cytometry. Results are interpreted in context of clinical findings, specimen quality, and comparison with peripheral blood lymphocyte counts. Values are typically reported as absolute count (#/volume) and percentage of total cells analyzed.N/A

Specimen: serum

No special patient preparation required. Specimen should be collected prior to administration of immunosuppressive or chemotherapeutic agents when possible. Inform laboratory of current medications including corticosteroids and immunomodulatory drugs.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: Immune Monitoring and Diagnosis

Short name

CD4/CD45 Blood Cell Count

Frequently asked questions

What does a low CD4/CD45 count mean for my health?
A low count of these cells can signal weakened immune function, increasing your risk of infections. For example, CD4 cells are critical for fighting viruses like HIV, while CD45 cells help identify overall leukocyte health. Your provider will discuss this with you based on your medical history and symptoms.
How often should I get this test if I have a condition like HIV?
If you have an immune-related condition, like HIV, your provider may order this test regularly to track changes in your immune system. Frequency depends on your treatment plan, disease progression, and response to therapy.
Can diet or lifestyle affect these test results?
While diet and lifestyle can influence overall blood health, they rarely directly affect CD4/CD45 cell counts. However, maintaining good health can support your immune system overall. Always follow your provider’s advice regarding test timing and preparation.
  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