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CK HMW (CK903/34BE12)
- Immunohistochemistry (IHC)
CK903 (34βE12) is a high molecular weight cytokeratin present in all squamous epithelium and their carcinomas. This antibody recognizes cytokeratins 1, 5, 10 and 14 that are found in complex epithelia. There has been no reactivity with cells derived from simple epithelia, mesenchymal tumors, lymphomas, melanomas, neural tumors and neuroendocrine tumors. One useful application is the identification of the basal cell layer in prostate tissue in the determination of carcinoma.
Specimen Requirements
A formalin-fixed, paraffin-embedded (FFPE) tissue block is preferred specimen type or one (1) unbaked, unstained slide for H&E staining (required) and two to three (2-3) positively charged unstained slides (all cut at 4-5 microns) for each test/antibody ordered.
Block and slide identifiers should be clearly written and match exactly with the specimen ID and specimen labeling as noted on the requisition.
Storage and Transportation
Use cold pack for transport, making sure cold pack is not in direct contact with specimen. NYS clients please provide date and time of Collection.
CPT Code(s)*
88342 x 1 or 88341 x 1
*The CPT codes provided with our test descriptions are based on AMA guidelines and are for informational purposes only. Correct CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed.
Last Updated: August 12, 2025