Perforin/Granzyme B (Sendout)

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General Information

Lab Name
Perforin/Granzyme B (Sendout)
Lab Code
RPERGB
Epic Name
Not individually orderable in Epic.

Order Hyperinflammatory Lab Panel.
External Test Id
2903500
Description

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 Information: In this assay, peripheral blood is stained with both surface and intracellular monoclonal antibodies and analyzed using flow cytometry. The perforin or granzyme B percent positivity is reported both on natural killer (NK) cells and cytotoxic T cells (CTLs) defined as CD3+CD8+CD57+ T Cells. Perforin and granzyme B are expressed in cytoplasmic granules of CTLs and NK cells. The median fluorescence (MdFI) ratio of perforin is also reported as the ratio of the NK cell perforin MdFI divided by the isotype control MdFI, which can be used to asses decreased expression of perforin in NK cells. This assay is intended to be used as a screening test.

    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 Perforin/Granzyme B (Sendout) [RPERGB] and CD107a Mobilization (Sendout) [RCD107].

      Collection Note: Limited specimen stability. Samples must be received by the performing lab within 24 hours of collection, on days that align with Cincinnati's run schedule. Failure to follow collection guidelines may result in test cancellation.

      References
      1. Abdalgani M, Filipovich AH, Choo S, Zhang K, Gifford C, Villanueva J, Bleesing JJ, Marsh RA. Accuracy of flow cytometric perforin screening for detecting patients with FHL due to PRF1 mutations. Blood. 2015 Oct 8;126(15):1858-60. doi: 10.1182/blood-2015-06-648659. PMCID: PMC4828082; PMID: 26450956.
      Forms & Requisitions
      Synonyms
      2903500, Granzyme B, Hemophagocytic lymphohisticytosis, HLH, Hyperinflammatory Disorder, Perforin
      Components
      Code Name
      RPRPNK Perforin Positive NK
      RPRPTC Perforin Positive CD8+CD57+ T Cells
      RMDFIR MDFI Ratio Perforin NK
      RGRBNK Granzyme B Positive NK
      RGRBTC Granzyme B Positive CD8+CD57+ T Cells
      RPGRBI Perforin/Granzyme B Interpretation
      RPGRBC Perforin/Granzyme B Comment

      Interpretation

      Method

      Flow Cytometry

      Reference Range
      See individual components
      Ref. Range Notes

      Note: A new reporting format and associated reference ranges were implemented at Cincinnati Children's Hospital Laboratory on 10/14/2025.

      Reference Ranges (Effective 10/14/2025):

      Perforin Positive NK: ≥ 90%
      Perforin Positive CD8+CD57+ T Cells: ≥ 74%
      Perforin NK MDFI Ratio: ≥ 43
      Granzyme B Positive NK: ≥ 74%
      Granzyme B Positive CD8+CD57+ T Cells: ≥ 70%
      Interferences and Limitations

      This flow cytometry assay is intended to be used as a screening test. Screening tests are not 100% sensitive nor specific, and a normal result should not preclude molecular sequencing if a patient's clinical presentation suggests that the probability of a diagnosis is high.

      References
      1. Abdalgani M, Filipovich AH, Choo S, Zhang K, Gifford C, Villanueva J, Bleesing JJ, Marsh RA. Accuracy of flow cytometric perforin screening for detecting patients with FHL due to PRF1 mutations. Blood. 2015 Oct 8;126(15):1858-60. doi: 10.1182/blood-2015-06-648659. PMCID: PMC4828082; PMID: 26450956.

      Ordering & Collection

      Specimen Type
      Blood
      Collection

      3 mL LAVENDER TOP (EDTA) tube

      Collection Notes:

      • Collect samples Monday through Thursday only due to Cincinnati's run schedule and short stability of the sample. Avoid collections on Fridays, weekends, holidays, or the day before a holiday.
      • Samples must be received by the performing lab within 24 hours of collection. Recommended to collect between 10:00 a.m. and 1:00 p.m. to ensure delivery within the stability limit.
      • 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 Delivery Express courier. Call UW-MT Sendouts team to notify them of an incoming sample for same-day shipment.

      Forms & Requisitions
      Approval Required
      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 Perforin/Granzyme B (Sendout) [RPERGB] and CD107a Mobilization (Sendout) [RCD107].
      Handling Instructions

      Outside Laboratories: Due to sample stability and shipping considerations, this test is not available outside of the UW Medicine system. Clients should arrange for testing directly with Cincinnati Children's Hospital Laboratory.

      Quantity
      Requested: 3 mL EDTA whole blood
      Minimum: 2 mL EDTA whole blood

      Processing

      Receiving Instructions

      UW-MT SPS: Store whole blood samples 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 Delivery Express courier. Call UW-MT Sendouts team at 206-598-3423 to notify them of an incoming sample for same-day shipment.

          Sendouts:

          • Order Cincinnati Children's Test: 2903500
          • Complete a Cincinnati Children's Diagnostic Immunology Laboratory Requisition.
          • Samples must arrive at Cincinnati within 24 hours of collection. Ship samples at ambient temperature to the address below, Monday through Thursday only, using FedEx First Overnight priority.
            • CCHMC CDBI Laboratories
            • 3333 Burnet Ave
            • DIL 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 >24 hrs after collection.

          Misc Sendout

          Performance

          Lab Department
          Sendouts(SO)
          Frequency
          Performed: Monday through Friday. Reported: 2 business days from sample receipt at Cincinnati Children's.
          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 (CBDI):

          • Phone: 513-636-4685
          • Fax: 513-636-3861
          • Lab Hours: Monday through Friday, 08:00 a.m. to 5:00 p.m EST
          • Email: CBDILabs@cchmc.org

          Billing & Coding

          CPT Codes
          88184, 88185x4
          LOINC
          33719-6
          Interfaced Order Code
          UOW6485