CD107a Cytotoxic Lymphocyte Exocytosis Assay (Sendout)

Test Utility: This test is ordered as part of the workup for hyperinflammatory syndromes such as hemophagocytic lymphohistiocytosis (HLH). This test should be ordered concurrently or after Hyperinflammatory Screening Labs have been obtained (CBC with diff, ferritin, fibrinogen, triglycerides, LDH, and D-dimer).

The following are consistent with, but not specific for, a diagnosis of HLH:

-Elevated sIL-2R, CXCL-9, and IL-18
-Elevated sCD163
-Reduced NK function (or cell surface expression of CD107alpha)
-Reduced perforin, SAP, or XIAP

Test Description: This CD107a Cytotoxic Lymphocyte Exocytosis Assay (CLEA) is a flow cytometric assay is intended to determine surface upregulation of CD107a as an indicator of degranulation of CD3-CD56+ natural killer (NK) cells after stimulation with K562 cells and anti-CD16-coated target cells. Degranulation is assessed by measuring CD107a upregulation on CD3-CD56+ natural killer (NK) cells and is reported as the percentage of CD107a positive and CD107a bright NK cells following stimulation with K562 cells and anti-CD16-coated target cells. Stimulation with K562 target cells assesses natural NK cell cytotoxic function, while stimulation with anti-CD16-coated targets evaluates antibody dependent cellular cytotoxicity (ADCC). The %CD107a value represents the proportion of NK cells demonstrating degranulation after subtraction of background signal from the unstimulated control. The %CD107a bright identifies the percentage of NK cells with robust degranulation, defined by a fluorescence intensity threshold set at 15 standard deviations above the median fluorescence intensity (MFI) of the unstimulated control.

Ordering Requirements: Laboratory Medicine Resident (LMR) approval is required for the Hyperinflammatory Lab Panel to help ensure that when this panel is indicated, collections are timed appropriately to meet stability limits for this test and Perforin/Granzyme B (Sendout) [RPERGB].

Collection Note: Limited specimen stability. Samples must be received at Cincinnati Children’s Hospital Lab within 30 hours of collection, on days that align with Cincinnati Lab's run schedule. Time blood collections accordingly. Failure to follow collection guidelines may result in test cancellations.

***Note: CD107a Cytotoxic Lymphocyte Exocytosis Assay (CLEA) is offered as an alternative to CD107a Mobilization (Sendout) [RCD107], which has been taken offline at Cincinnati Children's as of 10/27/2026. Results will be reported under "Reference Lab Test 1" [SEND1]. A new battery will be available for this test on 01/04/2027.***

Collection Timing:

• Collect samples Monday through Wednesday only due to Cincinnati's run schedule and the short stability window. Avoid collections on Thursday/Friday, weekends, holidays, or the day before a holiday.
• Samples must be sent same-day so that reach the performing lab within 30 hours of collection. Recommended to collect between before 1:00 p.m. to ensure delivery within the stability limit.

Sample Requirements: 1 x 10 mL DARK GREEN (Na Heparin) tube (see exception below)

Volume Note: If the patient’s absolute lymphocyte count (ALC) is available, call 513-636-4685 or use the Custom Volumes by ALC sheet to obtain the precise amount of blood required for this assay. If the ALC is not available, 10 mL blood in Sodium Heparin (Dark Green) should be sufficient for patients who are not lymphopenic. For counts below 200 cells/mcL, consider waiting until count increases.

Expedite transport to the lab. Sample must be received in lab no later than 2:00 p.m. for same-day shipment.

FHCC: Forward samples to UW-MT immediately via STAT courier. Call UW-MT Sendouts team to notify them of an incoming sample for same-day shipment.

UW-MT SPS: Store whole blood specimens at ambient temperature. Notify Sendouts immediately upon receipt of sample. Samples must be shipped same-day.

FHCC SPS: Send samples to UW-MT immediately via STAT courier. Call UW-MT Sendouts team at 206-598-3423 to notify them of an incoming sample for same-day shipment.

Note: Orders can be left as RCD107; CAST will add SEND1 for reporting.

Sendouts:

• Order Cincinnati Children's Test: LAB00726
• Complete a Cincinnati Children's Diagnostic Immunology Laboratory requisition.
• Samples must arrive at Cincinnati within 30 hours of collection. Ship samples at ambient temperature to the address below, Monday through Wednesday only, using FedEx First Overnight priority.
  • CCHMC DIL
  • 3333 Burnet Ave
  • Room R2328
  • Cincinnati, OH 45229
• Document the FedEx Tracking Number on the requisition and notify Cincinnati DIL of an incoming sample by faxing to: 513-636-3861.

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

Reject Due to: Frozen, clotted, hemolyzed, or centrifuged specimens. Specimen collected in an unacceptable anticoagulant. Specimens received >30 hrs after collection.

CCHMC Diagnostic Immunology Laboratory:

• Phone: 513-636-4685
• Fax: 513-636-3861
• Lab Hours: Monday - Friday, 08:00 AM - 5:00 PM EST. No Saturday delivery. Closed on weekends and holidays.
• Shipping Address:
  • CCHMC DIL
  • 3333 Burnet Avenue
  • Room 2328
  • Cincinnati, OH 45229-3039
• Email: CBDILabs@cchmc.org