Table 2.
Analysis of PD-L1 tumour-cell staining concordance between PD-L1 IHC 22C3 and 28-8 assays across PD-L1 expression levels
| PD-L1 expression | All biopsies (n=1930) | Biopsies with a confirmed lung cancer diagnosis (n=412) | ||||||||
| ≥1% | ≥5% | ≥10% | ≥25% | ≥50% | ≥1% | ≥5% | ≥10% | ≥25% | ≥50% | |
| PPA (95% CI) |
97% (96 to 98) |
97% (95 to 98) |
98% (96 to 98) |
98% (97 to 99) |
99% (97 to 99) |
97% (95 to 99) |
97% (93 to 98) |
98% (95 to 99) |
98% (94 to 99) |
99% (96 to 100) |
| NPA (95% CI) |
97% (96 to 98) |
97% (96 to 98) |
98% (96 to 98) |
97% (96 to 98) |
96% (95 to 97) |
96% (92 to 98) |
94% (89 to 96) |
96% (93 to 98) |
96% (93 to 98) |
97% (94 to 99) |
| OPA (95% CI) |
97% (96 to 98) |
97% (96 to 97) |
98% (97 to 98) |
98% (97 to 98) |
97% (96 to 97) |
97% (95 to 98) |
95% (93 to 97) |
97% (95 to 98) |
97% (94 to 98) |
98% (96 to 99) |
| Cohen’s kappa (95% CI) |
0.94 (0.93 to 0.96) |
0.93 (0.92 to 0.95) |
0.95 (0.94 to 0.96) |
0.95 (0.93 to 0.96) |
0.92 (0.90 to 0.94) |
0.94 (0.90 to 0.97) |
0.90 (0.86 to 0.94) |
0.94 (0.91 to 0.97) |
0.93 (0.89 to 0.97) |
0.95 (0.92 to 0.98) |
PPA and NPA calculations use 28-8 as the reference standard.
IHC, immunohistochemistry; NPA, negative per cent agreement; OPA, overall per cent agreement; PD-L1, programmed death ligand 1; PPA, positive per cent agreement.