ARUP's Laboratory Test Directory

Lymphocyte Subset Panel 3 - T-Cell Subsets (CD4 and CD8), Absolute Counts Only : 0095853
[ image for: Time Sensitive]
Time Sensitive
  


Mnemonic: ABS

Methodology: Quantitative Flow Cytometry
Performed: Sun-Sat
Reported: 1-2 days
Specimen Required: Collect: Lavender Hemogard (EDTA), pink Hemogard (K2EDTA), or green Hemogard (sodium or lithium heparin). Hemogard tubes are preferred for laboratory safety.

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

Storage/Transport Temperature: CRITICAL ROOM TEMPERATURE.

Remarks: Specimens must be analyzed within 72 hours of collection in EDTA or within 48 hours in heparin. 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.

Unacceptable Conditions: Frozen or refrigerated specimens. Specimens older than 72 hours in EDTA or 48 hours in heparin. Clotted or hemolyzed specimens.

Stability (collection to initiation of testing): Ambient: 72 hours in EDTA, 48 hours in heparin; Refrigerated: Unacceptable; Frozen: Unacceptable
Reference Interval:
Reports include age appropriate reference intervals and interpretation.
Components Reference Interval
Absolute CD4 (Helper T-cells) By report
Absolute CD8 (Suppressor T-cells) By report
Absolute CD3 (Total T-cells) By report
CD4: CD8 ratio By report

Interpretive Data: In this test, the CD4 cells are Helper T-cells because they express both CD3 and CD4. The CD8 cells are Suppressor T-cells because they express both CD3 and CD8. Helper T-cell levels are a criterion for categorizing HIV-related clinical conditions by the CDC's classification system for HIV infection. The measurement of Helper T-cell levels has been used to establish decision points for initiating P. jiroveci prophylaxis, antiviral therapy and to monitor the efficacy of treatment. The Public Health Service (PHS) has recommended that Helper T-cell levels be monitored every three to six months in all HIV-infected persons.

The performance characteristics of this test were determined by ARUP Laboratories, Inc.

See Compliance Statement B: www.aruplab.com/CS
Note: This assay is designed for enumerating the absolute cell counts of lymphocyte subsets 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.
CPT Code(s): 86359; 86360
Cross References: Absolute CD4 and CD8 (Lymphocyte Subset Panel 3-T-Cell Subsets (CD4 & CD8), Absolute Count), Lymphocyte Subset CD4 and CD8 (Lymphocyte Subset Panel 3-T-Cell Subsets (CD4 & CD8), Absolute Count)