Time Sensitive

Ordering Recommendation

Evaluate NK cells in patients with suspected immune deficiency.

New York DOH Approval Status

This test is New York state approved.

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: Same as the above.


Quantitative Flow Cytometry




1-3 days

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
Reference Interval
  % Natural Killer Cells
Age Reference Interval (Percent)
0-6 days 8-62
1 week-1 month 3-23
2-4 months 2-20
5-8 months 2-36
9-14 months 1-64
15-23 months 1-96
2-4 years 2-25
5-9 years 2-31
10-15 years 4-51
16-64 years 4-26
65 years or older 5-28

  Absolute Natural Killer Cells
Age Reference Interval (cells/µL)
0-6 days 500-3100
1 week-1 month 140-1900
2-4 months 97-2000
5-8 months 68-3900
9-14 months 71-3500
15-23 months 55-4000
2-4 years 61-510
5-9 years 70-590
10-15 years 92-1200
16-64 years 78-470
65 years or older 74-620

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.

This test was developed and its performance characteristics determined by ARUP Laboratories. It has not been cleared or approved by the US Food and Drug Administration. This test was performed in a CLIA certified laboratory and is intended for clinical purposes.

Compliance Category

Laboratory Developed Test (LDT)


Hotline History


CPT Codes



Component Test Code* Component Chart Name LOINC
0092403 Natural Killer Cell Information 77202-0
0095701 % Natural Killer Cells 32519-1
0095702 Absolute Natural Killer Cells 20604-5
* 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
Natural Killer Cells Enumeration