ARUP's Laboratory Test Directory
| 0095885: Lymphocyte Subset Panel 2 - CD4 Percent & Absolute |
![[ image for: Time Sensitive]](icon_1.jpg){kind=icon} | Time Sensitive |
| Test Mnemonic: CD4 | |
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Methodology: Flow Cytometry
Performed: Sun-Sat Reported: 1-3 days |
| Specimen Required: | |
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Collect: One 5 mL green Hemogard (sodium or lithium heparin) or one 5 mL lavender Hemogard (EDTA) or pink Hemogard (K2EDTA), labeled with the patient's name, date and time of draw. (Min: 3 mL) Pour-off tubes are no longer acceptable.
Transport: 5 mL whole blood at 20-25°C. (Min: 0.5 mL) Submit specimen according to Biological Substance, Category B, shipping guidelines. Pediatric Collection/Transport: 0.5 mL whole blood at 20-25°C. Submit specimen according to Biological Substance, Category B, shipping guidelines. Remarks: CRITICAL AMBIENT. Only Hemogard tubes are acceptable. Specimens must be analyzed within 48 hours of collection. 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: Clotted, hemolyzed, refrigerated, or frozen specimens. Specimens sent in pour-off tubes. Specimens older than 48 hours. Specimens collected in ACD (yellow). Stability: Ambient: 48 hours; Refrigerated: Unacceptable; Frozen: Unacceptable |
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| Interpretive Data: | |
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In this test, the CD4 cells are Helper T-cells because they express both CD3 and CD4. 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. |
| Note: | |
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This assay is designed for enumerating the percents and absolute cell counts of CD4 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, percents and 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): | |
| 88184 First marker; 88185 Additional marker |