Natural Killer Cell Activity (Sendout)

General Information

Lab Name

Natural Killer Cell Activity

Lab Code

RNKCA

Epic Name

(not orderable in Epic)

External Test Id

2900800

Description

Test Information: Natural Killer (NK) cells are a subset of cytotoxic lymphocytes that have the ability to induce cell death in tumor cells or in virally infected cells. NK cells play a crucial role in the homeostasis of the immune system. They are typically characterized by the expression of CD16 and CD56 on their cell surface.

This assay makes use of the fact that NK cells will lyse the human erythroleukemia cell line, K562, in vitro. K562 cells are loaded with radioactive chromium and incubated with various ratios of a mononuclear cell preparation. Lysis of the K562 targets by NK cells contained in the cell preparation is measured by the amount of chromium released into the supernatant.

Collection Note: Limited sample stability. Time specimen collections accordingly to ensure that samples arrive at Cincinnati Children's within 24 hours of collection.

***Order Alert: Effective 08/10/2026, this test is permanently offline at Cincinnati Children's Hospital Laboratories. For patients that need to be screened for genetic causes of HLH, Cincinnati recommends two different tests in lieu of the NK Cell Function Assay: CD107a Mobilization (Sendout) [RCD107] and Perforin/Granzyme B (Sendout) [RPERGB]. For male patients, SAP/XIAP testing can also be considered. Providers should contact the Laboratory Medicine Resident (LMR) on-call for additional ordering guidance.***

Synonyms

2900800, HLH, Killer Cells, Natural Killer Cells, NK Cells, NK Function

Components

Code	Name
RNKCAR	NK Cell Activity Result
RNKCAI	NK Cell Activity Interpretation
RNKCAC	NK Cell Activity Comment