Time Sensitive

Ordering Recommendation

Use to enumerate NK- and NKT-cell populations. This is not a NK-cell activity assay and should not be used as part of the diagnostic criteria for hemophagocytic lymphohistiocytosis (HLH).




Semi-Quantitative Flow Cytometry




1-3 days

New York DOH Approval Status

This test is New York DOH approved.

Specimen Required

Patient Preparation

Lavender (EDTA), or Pink (K2EDTA).

Specimen Preparation

Transport 4 mL whole blood. (Min: 1 mL)

Storage/Transport Temperature


Unacceptable Conditions

Clotted or hemolyzed specimens


Specimens must be analyzed within 48 hours of collection.
New York State Clients: Same as the above.


Room temperature: 48 hours; Refrigerated: Unacceptable; Frozen: Unacceptable
New York State Clients: Same as the above.

Reference Interval

Effective August 17, 2020

Available Separately
Reference Interval
No Pct CD3-CD16-/+CD56br/dim(total NKcells) 5.0 - 32.5 %
No Abs CD3-CD16-/+CD56br/dim(total NKcells) 91 - 593 cells/µL
No Pct CD3-CD16+CD56dim(cytotoxic NK-cells) 47.0 - 94.5 %
No Abs CD3-CD16+CD56dim(cytotoxic NK-cells) 51 - 482 cells/µL
No Pct CD3-CD16-CD56br (cyto secreting NK) 0.7 - 6.3 %
No Abs CD3-CD16-CD56br (cyto secreting NK) 2 - 16 cells/µL
No Pct CD3+CD56+ (CD56 NKT-cells) 0.9 - 14.4 %
No Abs CD3+CD56+ (CD56 NKT-cells) 20-349 cells/µL
No Pct CD45+CD3+ (T-cells) 59.0 - 86.9 %
No Abs CD45+CD3+ (T-cells) 654 - 2634 cells/µL
No Pct CD45+CD3-(Non T-cells) 15.7 - 43.6 %
No Abs CD45+CD3-(Non T-cells) 196 - 897 cells/µL
No Natural Killer T-cell Panel Interp See Note

Interpretive Data

Natural killer (NK) cells are identified by the absence of CD3 and the expression of CD16 and/or CD56. NK cells are divided according to the expression of CD16 and CD56 into cytotoxic NK cells (CD3-CD16+CD56dim) that represents approximately 90 percent of NK cells, and cytokine-secreting or regulatory NK cells (CD3-CD16-CD56bright) that represents approximately 10 percent of NK cells. NK cells act against virally-infected cells and tumor cells and may be increased or decreased in various immunologic abnormalities. NK cells also have a role in the adaptive immune response through cytokine production. NK-like T-cells have properties of both T-cells and NK-cells, expressing both CD3 and NK-associated antigens.

The cytotoxic NK cells (CD3-CD16+CD56dim) and cytokine-secreting or regulatory NK cells (CD3-CD16-CD56bright) are reported as a percentage of the total NK cells. All other populations are reported as a percentage of the total lymphocytes.

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

86356 x3; 86357; 86359


Component Test Code* Component Chart Name LOINC
2013806 Pct CD3-CD16-/+CD56br/dim(total NKcells) 8112-5
2013807 Abs CD3-CD16-/+CD56br/dim(total NKcells) 9728-7
2013808 Pct CD3-CD16+CD56dim(cytotoxic NK-cells) 8112-5
2013809 Abs CD3-CD16+CD56dim(cytotoxic NK-cells) 9728-7
2013810 Pct CD3-CD16-CD56br (cyto secreting NK)
2013811 Abs CD3-CD16-CD56br (cyto secreting NK)
2013814 Pct CD3+CD56+ (CD56 NKT-cells) 17135-5
2013815 Abs CD3+CD56+ (CD56 NKT-cells) 26858-1
2013818 Pct CD45+CD3+ (T-cells) 56907-9
2013819 Abs CD45+CD3+ (T-cells) 89312-3
2013820 Pct CD45+CD3- (Non T-cells) 89311-5
2013821 Abs CD45+CD3- (Non T-cells) 89313-1
2013822 Natural Killer T-cell Panel Interp 80722-2
* 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 and Natural Killer T-Cell Panel