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PD-L1 22C3 FDA (KEYTRUDA®) for HNSCC (Head & Neck)
- Immunohistochemistry (IHC)
PD-L1 IHC 22C3 pharmDx is a qualitative immunohistochemical assay using Monoclonal Mouse Anti-PD-L1, Clone 22C3 intended for use in the detection of PD-L1 protein in formalin-fixed, paraffin-embedded (FFPE) head and neck squamous cell carcinoma (HNSCC) and certain other tissues using EnVision FLEX visualization system on Autostainer Link 48. PD-L1 IHC 22C3 pharmDx is indicated as an aid in identifying HNSCC patients for treatment with KEYTRUDA® (pembrolizumab). KEYTRUDA® is approved for use in some HNSCC patients whose tumors express PD-L1 with Combined Positive Score (CPS) 1. For other tumor types with approved indications for this test, please search our Test Menu for 22C3 to see available options.
Specimen Requirements
A formalin-fixed, paraffin-embedded (FFPE) tissue block is preferred specimen type or one (1) unbaked, unstained slide cut at 4-5 microns for H&E staining (required) and two to three (2-3) positively charged unstained slides cut at 3-4 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. For PD-L1 22C3 evaluation, tissue submitted must have 100 viable tumor cells present.
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)*
88360x1
*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: July 28, 2025