Natural Killer Cells Enumeration
Ordering Recommendation

Evaluate NK cells in patients with suspected immune deficiency.

Quantitative Flow Cytometry
1-3 days
New York DOH Approval Status
This test is New York DOH approved.
Submit With Order
Time SensitiveTime Sensitive
ARUP Consult®
Disease Topics
Specimen Required
Patient Preparation
Lavender (EDTA), pink (K2EDTA), or green (sodium or lithium heparin). Hemogard tubes are preferred for laboratory automation and safety. 
Specimen Preparation
Transport 4 mL whole blood. (Min: 0.5 mL) 
Storage/Transport Temperature
Unacceptable Conditions
Clotted or hemolyzed specimens. 
Specimens must be analyzed within stability times provided. Some medication may affect immunophenotyping results and should be provided on the patient test request form. 
EDTA: Ambient: 72 hours; Refrigerated: Unacceptable; Frozen: Unacceptable
Heparin: Ambient: 48 hours; Refrigerated: Unacceptable; Frozen: Unacceptable
New York State Clients: EDTA: Ambient: 30 hours; Refrigerated: Unacceptable; Frozen: Unacceptable
Heparin: Ambient: 48 hours; Refrigerated: Unacceptable; Frozen: Unacceptable 
Reference Interval
Effective November 16, 2015

Reference Interval Notes:
Pediatric reference values (0 - 6 days up to 10 - 15 years) taken from Scandinavian Journal of Immunology 2012; 75, 436-444.
Adult and Geriatric (16 - 64 and 65 plus years) ranges were developed in-lab.
Test Number
Components0-6 days1 week - 1 month2-4 months5-8 months9-14 months15-23 months2-4 years5-9 years10-15 years16-64 years65 years or older
% NK-cells8-62%3-23%2-20%2-36%1-64%1-96%2-25%2-31%4-51%4-26%5-28%
Absolute NK-cells500-3100 cells/µL140-1900 cells/µL97-2000 cells/µL68-3900 cells/µL71-3500 cells/µL55-4000 cells/µL61-510 cells/µL70-590 cells/µL92-1200 cells/µL78-470 cells/µL74-620 cells/µL

Interpretive Data
The results reported are the percentage of lymphocytes that are Natural killer (NK) cells and the absolute count of NK-cells per µL of blood. Only those cells that express CD45 and either CD16 or CD56 (or both) but not CD3 or CD19 are reported.

Compliance Statement B: For laboratory developed tests not using a RUO kit, and for FDA approved, cleared or 510(k) exempt assays with alterations. This test was developed and its performance characteristics determined by ARUP Laboratories. The U. S. Food and Drug Administration has not approved or cleared this test; however, FDA clearance or approval is not currently required for clinical use. The results are not intended to be used as the sole means for clinical diagnosis or patient management decisions.

Hotline History
Component Test Code*Component Chart NameLOINC
0092403Natural Killer Cell Information
0095701% Natural Killer Cells32519-1
0095702Absolute Natural Killer Cells20604-5
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.
  • Natural Killer Cell CD56/CD16, Percent and Absolute
  • NK absolute cell count and percentage