Table 2. Cohen’s kappa coefficient (K) results for the comparison between the reference protocol A and the others.
K values are shown including and excluding inhibited samples.
| Protocols | N | K value (95% CI) | Positive samples | Inhibited samples | N excluding inhibition | Discordant samples excluding inhibition | K value excluding inhibited samples (95% CI) |
|---|---|---|---|---|---|---|---|
| A-B | 123 | 0.79 (0.68–0.9) |
59 | 0 | 123 | 13 | 0.79 (0.68–0.9) |
| A-C | 62 | 0.17 (0.08–0.26) |
8 | 35 | 27 | 8 | 0.45 (0.18–0.72) |
| A-D | 62 | 0.29 (0.14–0.44) |
24 | 17 | 45 | 10 | 0.53 (0.3–0.77) |
| A-E | 25 | 0.92 (0.77–1) |
11 | 0 | 25 | 1 | 0.92 (0.77–1) |
| A-F | 25 | 0.76 (0.5–1) |
10 | 0 | 25 | 3 | 0.76 (0.5–1) |
| A-G | 64 | 0.92 (0.81–1) |
15 | 2 | 62 | 0 | 1 |
| A-H | 64 | 1 | 15 | 0 | 64 | 0 | 1 |
N: number of samples assessed in parallel by both protocols compared. Positive samples: number of samples with a positive result for both protocols. Inhibited samples: number of samples with an invalid result for the internal amplification control (IAC) in at least one of the two protocols compared. CI: confidence interval.