Natural Killer Cell Activity (Sendout)

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General Information

Lab Name
Natural Killer Cell Activity
Lab Code
RNKCA
Epic Name
Natural Killer Cell Activity (Sendout)
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 (05/14/2025): This test is temporarily unavailable at Cincinnati Children's Hospital Laboratories due to a reagent manufacturing issue. The issue is expected to be resolved by early June 2025. 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: Perforin/Granzyme B (Sendout) [RPERGB] and CD107a Mobilization (Sendout) [RCD107]. For male patients, SAP/XIAP testing can also be considered. Providers should contact the Laboratory Medicine Resident (LMR) on-call for additional ordering guidance.***

          Lab Staff: Contact the Laboratory Medicine Resident (LMR) on call for any orders received while the test is offline.

          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

          Interpretation

          Method

          Chromium Release

          Reference Range
          See individual components
          Ref. Range Notes

          See report.

          Ordering & Collection

          Specimen Type
          Blood
          Collection

          Timing:

          • Specimen MUST be drawn Mon-Thurs only, between 10:00 am and 1:30 pm, and received in UW Lab by 2PM for same day shipment to referral lab.
          • Do not collect Friday through Sunday. Do not collect on or before a holiday.

          Collect: 10 mL blood in GREEN TOP (Sodium Heparin) tube

          • Exception: Patients with low ALC require higher volumes of blood; see note below.

          Note: 5-10mL blood in Sodium Heparin (Dark Green) is the general requirement and should be sufficient for patients who are not lymphopenic. Use the linked table below to determine the minimum amount of blood required for this assay for patients with Absolute Lymphocyte Count (ALC) values below 1.0x10^9 cells/L. Please note that this assay should not be performed on samples with an ALC of less than 0.2x10^9 cells/L.

          Expedite transport to laboratory. Specimen must be received by referral lab (Cincinnati Children's) within 24 hours of collection.

          Handling Instructions

          Outside Laboratories: Due to specimen stability limits, clients should arrange for testing directly with Cincinnati Children's Hospital Laboratory.

          If inquiring about a potential research study, please contact Dr. Mark Wener at 206 598-6131 for possibility of performing testing at UW-MT.

          Quantity
          Requested: 10 mL whole blood (Exceptions: See "Customized Volumes by ALC" under Collection)
          Minimum: 5 mL whole blood (Exceptions: See "Customized Volumes by ALC" under Collection)

          Processing

          Receiving Instructions

          ***Note 05/14/2025: This test is currently unavailable at Cincinnati Children's Hospital Laboratory. Contact the Laboratory Medicine Resident (LMR) on-call for any orders received while the test is offline. ***

          Hold and transport sample at room temperature (DO NOT refrigerate or freeze).

          • Expedited Processing Required. Notify sendouts staff immediately upon receipt of sample in the Lab.

          Sendouts:

          • Using the DIL requisition, order Cincinnati Children's Test: "NK Function" (2900800).
          • Samples must be shipped via FedEx First Overnight, Monday through Thursday only.
            • Call 513-636-4685 if a holiday falls during the week to confirm if a sample can be tested within the stability limit.
          • Notify the CINCL Diagnostic Immunology Lab of incoming samples by faxing a completed requisition and FedEx Shipping Label to: 513-636-3861.

          Stability: Ambient (Critical): 24 hours; Refrigerated: Unacceptable; Frozen: Unacceptable.

          Misc Sendout

          Performance

          Lab Department
          Sendouts(SO)
          Frequency
          Reported: 4 days from sample receipt at Cincinnati Children's Hospital Lab.
          Available STAT?
          No
          Performing Location(s)
          Sendout Cincinnati Children's Laboratories
          513-636-7355

          3333 Burnet Avenue
          Cincinnati, OH 45229
          Other Locations/Notes

          Cincinnati Children's Diagnostic Immunology Laboratory: 513-636-4685

          Billing & Coding

          CPT Codes
          86352, 86357
          LOINC
          34439-0
          Interfaced Order Code
          UOW4109