Table 1. Summary of literature study assessing agreement for PD-L1 scoring between the pathologists.
| Author (reference) | Antibody | Number of samples | Sample preparation | Number of pathologists | Cut points | Statistical test | Interobserver concordance | Gold standard |
|---|---|---|---|---|---|---|---|---|
| Cooper et al. (3) | 22C3 | 60 | TMA | 10 | >1% and >50% | OPA | 84.2% for 1% cut point; 81.9% for 50% cut point | Lead investigators assessment |
| Brunnström et al. (8) | 28-8 22C3, SP142, SP263 | 55 | TMA | 7 | 6-step system | Weighted kappa | 0.71–0.96 | Consensus |
| Rehman et al. (9) | SP142 | 35 | Slides from 3 blocks | 5 | number percentages from 0–100% | ICC | 94% | – |
| Rimm et al. (7) | 28-8, 22C3, SP142, E1L3N | 90 | Slides | 13 | 6-step system; >1% and >50% | ICC; Fleiss kappa; Kendall concordance coefficient | 0.832–0.882; 0.537 for 1% cut point and 0.749 for 50% cut point; 0.612 for 1% cut point and 0.775 for 50% cut point |
Median pathologist score |
| Scheel et al. (10) | 28-8, 22C3, SP142, SP263 | 17 | Slides | 9 | 6-step system; 4-step system | Light’s kappa | 0.47–0.5; 0.6–0.8 | – |
OPA, overall percent agreement; ICC, interclass correlation coefficient; TMA, tissue microarrays.