Agreement between the 28-8 and 22C3 assays in matched sample pairs* in the overall population at the ≥1% tumour cell PD-L1 expression cut-off
| 28-8 as reference | 22C3 as reference | OPA | Cohen’s kappa | |||
| PPA | NPA | PPA | NPA | |||
| Agreement (95% CI) | 97 (96–98) | 96 (95–97) | 97 (96–98) | 97 (96–97) | 97 (96–97) | 0.94 (0.92–0.95) |
| n/N | 1656/1701 | 1298/1349 | 1656/1707 | 1298/1343 | 2954/3050 | |
*Patients with a matched biopsy and single test results for both the 28-8 and the 22C3 assay.
IHC, immunohistochemistry; n, number of patients with concordant results; N, total number of patients; NPA, negative percentage agreement; OPA, overall percentage agreement; PD-L1, programmed death ligand 1; PPA, positive percentage agreement.