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PD-L1 22C3 FDA (KEYTRUDA®) for TNBC (Breast)
- 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) triple-negative breast cancer (TNBC) tissue using EnVision FLEX visualization system on Autostainer Link 48. This test is indicated as an aid in identifying TNBC patients for treatment with KEYTRUDA® (pembrolizumab). Tissues with PD-L1 Combined Positive Score (CPS) ≥10 are considered positive. Stain-only (tech-only) testing is available to clients who have completed the test kit manufacturers online interpretation training. All PD-L1 IHC test options may be viewed here.
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. 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