Ordering Recommendation

Use for cervical carcinomas (squamous cell carcinomas and adenocarcinomas), esophageal squamous cell carcinoma (ESCC), head and neck squamous cell carcinoma (HNSCC), and triple-negative breast cancer (TNBC) specimens only, to aid in prediction of response to pembrolizumab (KEYTRUDA). Refer to the PD-L1 Testing Algorithm for more information.

New York DOH Approval Status

This test is New York state approved.

Specimen Required

Patient Preparation

Tumor tissue.

Specimen Preparation

Formalin fix (10 percent neutral buffered formalin) and paraffin embed specimen. Protect paraffin block and/or slides from excessive heat. Transport tissue block or 5 unstained (3- to 5-micron thick sections), positively charged slides in a tissue transport kit (ARUP supply #47808 recommended but not required), available online through eSupply using ARUP Connect™ or contact ARUP Client Services at (800) 522-2787. (Min: 3 slides) If sending precut slides, do not oven bake.

Storage/Transport Temperature

Room temperature. Also acceptable: Refrigerated. Ship in cooled container during summer months.

Unacceptable Conditions

Specimens with fewer than 100 viable tumor cells. Tumor types that do not have FDA approval for PD-L1 22C3 testing with combined positive score (CPS). Specimens fixed in any fixative other than 10 percent neutral buffered formalin. Decalcified and cell block specimens.


Include surgical pathology report and indicate tissue site with the test order. For additional technical details, please contact ARUP Client Services at (800) 522-2787.
If multiple specimens (blocks or slides) are sent to ARUP, they must be accompanied by one of the following: an order comment indicating that the ARUP pathologist should choose the specimen most appropriate for testing (e.g., "Choose best block"), or individual orders for each sample submitted. A Pathologist Block Selection Fee (ARUP test code 3002076) will be added to orders that utilize the first option. If multiple specimens are sent to ARUP without a request for pathologist block/slide selection or individual orders, they will be held until clarification is provided.


Slides: Ambient: 5 months (Must be stored in the dark); Refrigerated: 5 months (Must be stored in the dark); Frozen: Unacceptable
Paraffin Block: Ambient: Indefinitely; Refrigerated: Indefinitely; Frozen: Unacceptable






1-5 days

Reference Interval

Interpretive Data

Refer to report.  

Compliance Category



This test code includes pathologist interpretation. At least 100 viable tumor cells are required for interpretation.

Hotline History


CPT Codes



Component Test Code* Component Chart Name LOINC
2012108 PD-L1 Client Block ID 94736-6
2013285 PDL1 Tissue Source 31208-2
2013286 Adequacy of Specimen
3000223 Combined Positive Score 83053-9
3000224 PDL1 22C3 IHC Result 83052-1
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.


  • Merck
  • PD-L1
  • PDL1
  • Pembro
PD-L1 22C3 IHC with Combined Positive Score (CPS) Interpretation, pembrolizumab (KEYTRUDA)