Natural Killer Cells Enumeration
Also known as: NK CELLS
Use
This test is used to evaluate natural killer (NK) cells in patients with suspected immune deficiency. NK cells play a critical role in the body's immune defense mechanisms, particularly in recognizing and destroying virally infected cells and tumor cells without prior sensitization. The test quantifies the percentage of lymphocytes that are NK cells and provides the absolute count of NK cells per microliter of blood. It is particularly useful in diagnosing and managing conditions associated with immune deficiency and immune regulation disorders.
Special Instructions
Specimens must be analyzed within the stability times provided to ensure accurate results. It is important to provide information about any medications the patient is taking on the test request form, as some medications may affect immunophenotyping results.
Limitations
The test results are limited to cells that express CD45 and either CD16 or CD56 but not CD3 or CD19. The methodology used is quantitative flow cytometry, which is precise for these specific markers. However, variations in sample handling or the presence of clots and hemolysis can lead to specimen rejection. Additionally, the test does not detect or report NK cells that do not meet the specified criteria for expression markers.
New York Approved
Methodology
Cell-based / Cytometry (Flow Cytometry)
Biomarkers
LOINC Codes
- 77202-0
- 32519-1
- 20604-5
Result Turnaround Time
1-3 days
Related Documents
For more information, please review the documents below
Specimen
Whole Blood
Volume
4 mL
Minimum Volume
0.5 mL
Container
Lavender (EDTA), pink (K2EDTA), or green (sodium or lithium heparin) tubes. Hemogard tubes are preferred for laboratory automation and safety.
Storage Instructions
CRITICAL ROOM TEMPERATURE.
Causes for Rejection
Clotted or hemolyzed specimens.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | EDTA: 72 hours; Heparin: 48 hours |
| Refrigerated | Unacceptable |
| Frozen | Unacceptable |