PD-L1 LDT

Programmed cell death ligand 1 (PD-L1) is a transmembrane protein involved in cellular and humoral immune response regulation. PD-L1 expression has been found in a variety of cancers expressed on tumor and/or immune cells. This lab developed test uses the Zeta PD-L1 monoclonal antibody clone ZR3 to detect PD-L1 in formalin-fixed paraffin-embedded tissues. The utility of PD-L1 (ZR3) in predicting the response to anti-PD-1/PD-L1 has not been determined and no standardized scoring criteria currently exist. For therapies and indications that have an FDA-approved PD-L1 companion diagnostic, it is recommended to use the associated FDA approved PD-L1 test. All PD-L1 IHC test options may be viewed here. Scoring for this test is called Total PD-L1 Expression and is calculated by dividing the sum of the number of staining tumor cells and inflammatory cells by the total number of viable tumor cells. Results are reported as detected if the total score is a 1 and not detected if