ARUP's Laboratory Test Directory

Lymphocyte Subset Panel 6 - Total Lymphocyte Enumeration with CD45RA & CD45RO : 0095862
[ image for: Time Sensitive]
Time Sensitive
  


Mnemonic: TEXTENDED

Methodology: Flow Cytometry
Performed: Sun-Sat
Reported: 1-3 days
Specimen Required: 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.

Storage/Transport Temperature: 5 mL whole blood at 20-25°C. (Min: 0.5 mL)

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.

New York State Clients: Only EDTA specimens may be submitted and must be analyzed within 30 hours of collection.

Unacceptable Conditions:  Clotted, hemolyzed, refrigerated, or frozen specimens. Specimens sent in pour-off tubes. Specimens collected in ACD (yellow) tubes.  Specimens older than 48 hours.
New York State Clients: Clotted, hemolyzed, refrigerated, or frozen specimens. Specimens sent in pour-off tubes. Specimens collected in ACD (yellow) tubes or heparin. EDTA specimens older than 30 hours.

Stability (collection to initiation of testing):  Ambient: 48 hours; Refrigerated: Unacceptable; Frozen: Unacceptable
New York State Clients: Ambient: 30 hours; Refrigerated: Unacceptable; Frozen: Unacceptable
Reference Interval:
Reports include age appropriate reference intervals and interpretation.
 
Components Reference Interval
% CD4  (Helper T-cells)
Absolute CD4 		By report
% CD45RA (Naive helper T-cells)
Absolute CD45RA 		By report
% CD45RO (Memory helper T-cells)
Absolute CD45RO 		By report
% CD8 (Suppressor T-cells)
Absolute CD8 		By report
CD4: CD8 ratio By report
% CD3 (Total T-cells)
Absolute CD3 		By report
% CD19 (B-cells)
Absolute CD19 		By report
% NK-cells
Absolute NK-cells 		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. The B-cells express CD19 but not CD3. The NK-cells express either CD16 or CD56 (or both) but not CD3. The CD45RA cells express both CD4 and CD45RA and the CD45RO cells express both CD4 and CD45RO. 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 and 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: This assay is designed for enumerating the percents and 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, 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.

The CD45RA subset delineates a "naive" helper T-cell population. The CD45RO subset delineates a "memory" helper T-cell population. With disease progression in HIV-infected individuals, a decrease in CD45RA "naive" cells may be observed.

For longitudinal studies involving serial monitoring, specimen collections should be performed at the same time of day.
CPT Code(s): 88184 First marker; 88185 x7 Each additional marker
Cross References: T-Cell Immunodeficiency Extended Profile
 
 

 

 

 
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