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Immunohistochemistry (IHC)
Test Description

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) urothelial carcinoma 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 urothelial carcinoma patients for treatment with KEYTRUDA® (pembrolizumab). Keytruda® is approved for use in some urothelial carcinoma patients whose tumors express PD-L1 with Combined Positive Score (CPS) ≥ 10.

For gastric or GEJ cancer, please order PD-L1 22C3 FDA (KEYTRUDA®) for Gastric/GEA. For cervical cancer, please order PD-L1 22C3 FDA (KEYTRUDA®) for Cervical. For non-small cell lung carcinoma (NSCLC), please order PD-L1 22C3 FDA (KEYTRUDA®) for NSCLC.

Stain-only (tech-only) testing is available to clients who have completed the test kit manufacturer’s online interpretation training.

Specimen Requirements
  • A formalin-fixed, paraffin-embedded (FFPE) tissue block is preferred specimen type
  • 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.
Storage and Transportation

Use cold pack for transport. Make sure cold pack is not in direct contact with specimen.

CPT Code(s)*
Turnaround Time

Global: 48 hours, Tech-Only (stain only): 24 hours


1. PD-L1 IHC 22C3 pharmDx [package insert]. Carpinteria, CA: Dako; P03951_11/SK00621-5/2018.09 
2. KEYTRUDA® (pembrolizumab) [package insert]. Whitehouse Station, NJ: Merck & C o., Inc: uspi-mk3475-iv-1810r019

New York Approved
Level of Service
Stain Only

*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.