Table 3. Diagnostic differences between ELISA tests used for samples collected in Ireland (April 2013) and in Belgium (September 2016) with inclusion of suspect/doubtful in the negative results (a) and in the positive results (b).
| a) Suspect/doubtful included in the negative results | |||||
| PPA (%) | NPA (%) | a κ | |||
| Ireland | IDEXX | 37 (25–50) | 78 (40–96) | 0.05 (0.06) | |
| ID.Vet | 88 (77–95) | 67 (31–91) | 0.46 (0.14) | ||
| Belgium | Ewes | IDEXX | 77 (54–91) | NA | NA |
| ID.Vet | 91 (69–98) | NA | NA | ||
| Lambs | IDEXX | 64 (46–79) | 97 (84–100) | 0.61 (0.08) | |
| ID.Vet | 97 (84–100) | 100 (88–100) | 0.97 (0.12) | ||
| b) Suspect/doubtful included in the positive results | |||||
| PPA (%) | NPA (%) | a κ | |||
| Ireland | IDEXX | 47 (34–60) | 78 (40–96) | 0.10 (0.07) | |
| ID.Vet | 95 (83–98) | 67 (31–91) | 0.57 (0.14) | ||
| Belgium | Ewes | IDEXX | 95 (75–100) | NA | NA |
| ID.Vet | 95 (75–100) | NA | NA | ||
| Lambs | IDEXX | 86 (70–95) | 97 (94–100) | 0.83 (0.06) | |
| ID.Vet | 100 (88–100) | 100 (88–100) | 1.00 (0.02) | ||
Abbreviations: PPA—positive percentage of agreement, NPA—negative percentage of agreement, κ - Cohen’s Kappa
a For each κ value, the standard error is indicated between the brackets. NA—an error if the calculations could not be achieved due to the properties of the tested population.