Agreement between the 28-8 and 22C3 assays in matched sample pairs* from patients with lung cancer, melanoma, SCCHN and UC 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 | |||
| Lung | 0.93 (0.91–0.95) | |||||
| Agreement (95% CI) | 97 (96–98) | 96 (94–97) | 98 (96–98) | 96 (94–97) | 97 (96–98) | |
| n/N | 868/893 | 560/582 | 868/890 | 560/585 | 1428/1475 | |
| Melanoma | 0.94 (0.83–1.05) | |||||
| Agreement (95% CI) | 100 (81–100) | 95 (75–100) | 94 (73–100) | 100 (82–100) | 97 (85–100) | |
| n/N | 16/16 | 18/19 | 16/17 | 18/18 | 34/35 | |
| SCCHN | 0.82 (0.59–1.06) | |||||
| Agreement (95% CI) | 100 (76–100) | 81 (52–95) | 86 (60–96) | 100 (70–100) | 91 (73–98) | |
| n/N | 12/12 | 9/11 | 12/14 | 9/9 | 21/23 | |
| UC | 1.00 (1.00–1.00) | |||||
| Agreement (95% CI) | 100 (72–100) | 100 (34–100) | 100 (72–100) | 100 (34–100) | 100 (76–100) | |
| n/N | 10/10 | 2/2 | 10/10 | 2/2 | 12/12 | |
*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; SCCHN, squamous cell carcinoma of the head and neck; UC, urothelial carcinoma.