Patient Preparation

 

Collect

Lavender (EDTA), pink (K₂EDTA), or green (sodium or lithium heparin). Hemogard tubes are preferred for laboratory automation and safety. 

Specimen Preparation

Transport 4 mL whole blood. (Min: 0.5 mL) 

Storage/Transport Temperature

CRITICAL ROOM TEMPERATURE. 

Unacceptable Conditions

Clotted or hemolyzed. 

Remarks

Specimens must be analyzed within stability times provided. Some medications may affect immunophenotyping results and should be listed on the patient test request form.
This test is not approved for New York State Clients 

Stability

EDTA: Ambient: 72 hours; Refrigerated: Unacceptable; Frozen: Unacceptable
Heparin: Ambient: 48 hours; Refrigerated: Unacceptable; Frozen: Unacceptable 

Effective November 16, 2015
Reports include age appropriate reference intervals and interpretation.

Reference Interval Notes:
Pediatric reference values (0 - 6 days up to 10 - 15 years) taken from Scandinavian Journal of Immunology 2012; 75, 436-444.
Adult and Geriatric (16 - 64 and 65 plus years) ranges were developed in-lab.

Test Number	Components	0-6 days	1 week - 1 month	2-4 months	5-8 months	9-14 months	15-23 months	2-4 years	5-9 years	10-15 years	16-64 years	65 years or older
	Absolute CD4	1000-4800 cells/µL	1500-6000 cells/µL	1600-6500 cells/µL	1000-7200 cells/µL	1300-7100 cells/µL	400-7200 cells/µL	500-2700 cells/µL	400-2500 cells/µL	400-2100 cells/µL	430-1800 cells/µL	490-1600 cells/µL

The CD4 cells are Helper T-cells expressing both CD3 and CD4. CD4 T-cell levels are a criterion for categorizing HIV-related clinical conditions by the CDC's classification system for HIV infection. The measurement of CD4 T-cell levels has been used to establish decision points for initiating P. jirovecii prophylaxis, antiviral therapy and to monitor the efficacy of treatment. The Public Health Service (PHS) has recommended that CD4 T-cell levels be monitored every 3 to 6 months in all HIV-infected persons.

This test is specifically designed for enumerating the absolute cell counts of Helper T-cells in lysed whole blood. Whole blood is added to fluorochrome-labeled antibodies that bind specifically to cell surface antigens on lymphocytes. After incubation, lysing and fixation, absolute counts are enumerated utilizing an internal quantitation standard. Additional CBC data is not required.

During HIV infection, antiviral therapy is often initiated when the absolute CD4 count drops below 500 cells/µL. When the absolute CD4 count drops below 200 cells/µL, therapeutic prophylaxis against PCP and other opportunistic infections may be initiated. When the absolute CD4 count drops below 100 cells/µL, prophylaxis against Mycobacterium avium complex is recommended.

For longitudinal studies involving serial monitoring, specimen collections should be performed at the same time of day.

86361

Component Test Code*	Component Chart Name	LOINC
0095854	Absolute CD4	24467-3

* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.

• Immune Status-Flow Cytometry
• CD4
• CD4 Count
• Helper T-Cell count
• P. jiroveci prophylaxis determination