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Test ID PAX8 PAX8 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

Supplies: Immunostain Technical Only Envelope (T693)

Specimen Type: Tissue

Container/Tube: Immunostain Technical Only Envelope

Preferred: 2 Unstained positively charged glass slide (25- x 75- x 1-mm) per test ordered; sections 4-microns thick

Acceptable: Formalin-fixed, paraffin-embedded (FFPE) tissue block

Useful For

Aids in the identification of renal cell carcinomas, as well as papillary thyroid carcinomas and tumors of Mullerian origin

Reflex Tests

Test ID Reporting Name Available Separately Always Performed
IHTOI IHC Initial, Tech Only No No
IHTOA IHC Additional, Tech Only No No

Method Name

Immunohistochemistry (IHC)

Reporting Name

PAX8 IHC, Tech Only

Specimen Type


Specimen Stability Information

Specimen Type Temperature Time Special Container
TECHONLY Ambient (preferred)

Clinical Information

PAX8 is a member of the paired box gene (PAX) family of transcription factors involved in kidney cell and thyroid development. PAX8 has been shown to be expressed in a high percentage of renal neoplasms, including both malignant renal cell carcinomas and benign renal tumors (oncocytomas). PAX8 has also been reported to be expressed in ovarian carcinomas.


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 855-516-8404.


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. Chang A, Brimo F, Montgomery EA, Epstein JI: Use of PAX8 and GATA3 in diagnosing sarcomatoid renal cell carcinoma and sarcomatoid urothelial carcinoma. Hum Pathol. 2013 Aug;44(8):1563-1568

2. Hu Y, Hartmann A, Stoehr C, et al: PAX8 is expressed in the majority of renal epithelial neoplasms: an immunohistochemical study of 223 cases using a mouse monoclonal antibody. J Clin Pathol. 2012 Mar;65(3):254-256

3. Laury AR, Perets R, Piao H, et al: A comprehensive analysis of PAX8 expression in human epithelial tumors. Am J Surg Pathol. 2011 Jun;35(6):816-826

4. Ozcan A, Shen SS, Hamilton C, et al: PAX8 expression in non-neoplastic tissues, primary tumors, and metastatic tumors: a comprehensive immunohistochemical study. Mod Pathol. 2011 Jun;24:751-764

5. Tacha D, Qi W, Zhou D, Bremer R, Cheng L: PAX8 mouse monoclonal antibody (BC12) recognizes a restricted epitope and is highly sensitive in renal cell and ovarian cancers but does not cross-react with B cells and tumors of pancreatic origin. Appl Immunohistochem Mol Morphol. 2013 Jan;21(1):59-63

6. Tacha D, Zhou D, Cheng L: Expression of PAX8 in normal and neoplastic tissues: a comprehensive immunohistochemical study. Appl Immunohistochem Mol Morphol. 2011 Jul;19(4):293-299

7. Kilgore MR, Bosch DE, Adamson KH, Swanson PE, Dintzis SM, Rendi MH: Unexpected PAX8 immunoreactivity in metastatic high-grade breast cancer. Appl Immunohistochem Mol Morphol. 2019 Oct;27(9):637-643. doi: 10.1097/PAI.0000000000000707

Day(s) Performed

Monday through Friday

Report Available

1 to 3 days

Test 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

Test ID Test Order Name Order LOINC Value
PAX8 PAX8 IHC, Tech Only Order only;no result


Result ID Test Result Name Result LOINC Value
70846 PAX8 IHC, Tech Only Bill only; no result


If not ordering electronically, complete, print, and send a Immunohistochemical (IHC)/In Situ Hybridization (ISH) Stains Request (T763) with the specimen.

Mayo Clinic Laboratories | IHC Catalog Additional Information: