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HelpTest ID IRF8 Interferon Regulatory Factor 8 (IRF8) Immunostain, Technical Component Only
Ordering Guidance
This test includes only technical performance of the stain (no pathologist interpretation is performed). If diagnostic consultation by a pathologist is required order PATHC / Pathology Consultation.
Shipping Instructions
Attach the green pathology address label and the pink Immunostain Technical Only label included in the kit to the outside of the transport container.
Specimen Required
Specimen Type: Tissue
Supplies: Immunostain Technical Only Envelope (T693)
Container/Tube: Immunostain Technical Only Envelope
Preferred:
-Formalin-fixed, paraffin-embedded tissue block
OR
-2 Unstained, positively charged glass slides (25- x 75- x 1-mm) per test ordered; sections 4-microns thick
Acceptable: None
Useful For
Identification of monoblasts in acute monoblastic/monocytic leukemia and chronic myelomonocytic leukemia
Reflex Tests
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| IHTOI | IHC Initial, Tech Only | No | No |
| IHTOA | IHC Additional, Tech Only | No | No |
Testing Algorithm
For the initial technical component only immunohistochemical (IHC) stain performed, the appropriate bill-only test ID will be reflexed and charged (IHTOI). For each additional technical component only IHC stain performed, an additional bill-only test ID will be reflexed and charged (IHTOA).
Method Name
Immunohistochemistry (IHC)
Reporting Name
IRF8 IHC, Tech OnlySpecimen Type
TECHONLYSpecimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| TECHONLY | Ambient (preferred) | ||
| Refrigerated | |||
Clinical Information
Interferon regulatory factor 8 (IRF8) is a marker for monocytic and dendritic cell progenitors. Expression of IRF8 is useful for detecting monoblasts in both acute monoblastic/monocytic leukemia and advancing chronic myelomonocytic leukemia. IRF8 expression is also observed in blastic plasmacytoid dendritic cell neoplasm and may be useful to distinguish classic Hodgkin lymphoma and anaplastic large cell lymphoma.
Interpretation
This test does not include pathologist interpretation, only technical performance of the stain. If interpretation is required, order PATHC / Pathology Consultation for a full diagnostic evaluation or second opinion of the case.
The positive and negative controls are verified as showing appropriate immunoreactivity and documentation is retained at Mayo Clinic Rochester. If a control tissue is not included on the slide, a scanned image of the relevant quality control tissue is available upon request; call 800-533-1710.
Interpretation of this test should be performed in the context of the patient's clinical history and other diagnostic tests by a qualified pathologist.
Clinical Reference
1. Katz SG, Edappallath S, Xu ML. IRF8 is a reliable monoblast marker for acute monocytic leukemias. Am J Surg Pathol. 2021;45(10):1391-1398
2. Tzankov A, Facchetti, F, Muhleisen B, Dirnhofer S. IRF8 is a reliable monoblast marker for acute monocytic leukemias, but does not discriminate between monoblasts and plasmacytoid dendritic cells. Am J Surg Pathol. 2022;46(5):725-727
3. McQuaid DC, Katz SG, Xu ML. IRF8 as a novel marker to differentiate between CD30-positive large cell lymphomas. Am J Clin Pathol. 2022;158(2):173-176
Day(s) Performed
Monday through Friday
Report Available
1 to 3 daysTest Classification
This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.CPT Code Information
88342-TC, primary
88341-TC, if additional IHC
LOINC Code Information
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 620065 | IRF8 IHC, Tech Only | No LOINC Needed |
Forms
If not ordering electronically, complete, print, and send a Immunohistochemical (IHC)/In Situ Hybridization (ISH) Stains Request (T763) with the specimen.
mcl-ihc