CD4 Count for Immune Monitoring, Blood
Use
This test is useful for serial monitoring of CD4 T cell count in patients who are HIV-positive, follow-up and diagnostic evaluation of primary cellular immunodeficiencies including severe combined immunodeficiency, T-cell immune monitoring following immunosuppressive therapy for transplantation, autoimmunity, and other conditions, and assessment of T-cell immune reconstitution post hematopoietic cell transplantation. It also serves as early screening for gross quantitative anomalies in T cells related to infection or malignancies. However, it should not be used for diagnosing T-lymphocytic malignancies or evaluation of T-cell lymphocytosis of unknown etiology.
Special Instructions
Date of collection is required. For serial monitoring, specimen collection is recommended at the same time of day. Specimens should arrive within 24 hours of collection. Collect and package specimens as close to shipping time as possible. If not ordering electronically, complete and send a Kidney Transplant Test Request form with the specimen.
Limitations
This assay should not be used for diagnosing T-lymphocytic malignancies or evaluation of T-cell lymphocytosis of unknown etiology. Abnormalities in CD3, CD4, and CD8 T cell numbers must be interpreted in context with the clinical presentation and other relevant laboratory test results. Lower CD4 T-cell counts are seen in the morning compared to the evening and during summer compared to winter, indicating the timing of blood collection is critical for monitoring. The assay excludes monocytes and calculates absolute counts using internal bead standards. 7-AAD is used to assess cell viability. For complete lymphocyte profiling, a T-cell, B-cell, and NK-cell quantitation assay may be more useful.
New York Approved
Methodology
Cell-based / Cytometry (Flow Cytometry)
Biomarkers
LOINC Codes
- 80721-4
- 8122-4
- 8123-2
- 24467-3
- 14135-8
- 54218-3
- 27071-0
- 8124-0
- 8101-8
- 69052-9
- 33193-4
Result Turnaround Time
1-2 days
Related Documents
For more information, please review the documents below
Specimen
Whole Blood
Volume
3 mL
Minimum Volume
1 mL
Container
Lavender top (EDTA)
Collection Instructions
Send whole blood specimen in original tube. Do not aliquot. For serial monitoring, it is recommended that specimen collection be performed at the same time of day.
Causes for Rejection
Gross hemolysis, Gross lipemia
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 72 hours |