Lab Test

CD4 Absolute Count

T-helper cell count, CD4 Absolute Count, CD4/CD8 ratio, Flow Cytometry, CD4 Absolute Count, T4/T8 Ratio

Test Codes



Flow Cytometry


  • Specimens should only be drawn Monday – Friday. The specimen should not be drawn on weekends or holidays. On the day before a holiday, specimens must be received in the Flow Cytometry Laboratory BEFORE 12:00 pm on the day before the holiday for testing to be performed.
  • A Complete Blood Count and Differential (CBCWD) is required to perform CD4 Absolute Count testing.

Specimen Collection Criteria

Collect: One Lavender-top EDTA tube for CD4 Absolute Count AND one Lavender-top EDTA tube for Complete Blood Count with Differential. (Minimum: 2.0 mL each tube.)

  • The second Lavender-top EDTA tube at room temperature is not required for CD4 Absolute Count if:
    • CBCWD is ordered for purpose not related to this test and drawn at the same time.
    • CBCWD is performed in the Outreach Client's office and results are faxed to the Flow Cytometry Laboratory (248-551-1262) and received at the time of testing.
  • If a separate specimen is NOT submitted for the Complete Blood Count with Differential, a CBCWD will be ordered.
  • A copy of the requisition must be sent with the specimen.

Physician Office/Draw Specimen Preparation

Maintain whole blood at room temperature (20-26°C or 68-78.8°F) prior to transport. Specimens MUST be received in the Laboratory within 24 hours of collection.

Preparation for Courier Transport

Transport: Whole blood, at room temperature (20-26°C or 68-78.8°F).

Transport two 4 mL whole blood tubes (minimum: 2 mL each tube) at room temperature. Specimens MUST be received within 24 hours of collection. No weekend or holiday draws.

Rejection Criteria

  • Clotted specimens.
  • Refrigerated specimens, accepted with approval of the Flow Cytometry manager or lab director.
  • Specimens received greater than 24 hours post collection.

In-Lab Processing

Maintain at room temperature (20-26°C or 68-78.8°F) prior to testing. The specimen should be processed within 24 hours of collection.


Specimen Stability for Testing:

Room Temperature (20-26°C or 68-78.8°F): 24 hours
Refrigerated (2-8°C or 36-46°F): Acceptable with approval of the Flow Cytometry supervisor or lab director.
Frozen (-20°C/-4°F or below): Unacceptable

Specimen Storage in Department Prior to Disposal:

Refrigerated (2-8°C or 36-46°F): 7 days


Royal Oak Flow Cytometry Laboratory


Monday – Friday, Saturday until 12:00 pm.
Results available in 1-2 days.

Reference Range

Age CD4 (mill/L) CD3 (mill/L)
0-6 months 2780-3908 3505-5009
6-12 months 2630-3499 3409-4575
12-18 months 2307-2864 3156-3899
18-24 months 1919-2472 2766-3508
24-30 months 1538-2213 2324-3295
30-36 months 1216-2000 1923-3141
3-18 years 562-2692 1072-3890
Adult 433-1722 730-2460


Age CD8 (mill/L)
Less than 3 years 351 - 2479
3-18 years 331-1445
Adult 143-921

Please see Pediatric Reference Range.

Test Methodology

Immunophenotyping by Multiparameter Flow Cytometry.


This assay includes: absolute lymphocyte count, CD4 T-helper cells, CD8 T-suppressor cells, and CD3 total T-cells.

Clinical Utility

This test may be used to monitor patients with HIV infection.

CPT Codes

86359, 86360, 88184.
LOINC: 54218-3, CD4 8123-2, CD8 8101-8, 24467-3


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