Table 4. Diagnostic performance of conventional diagnostic assays and novel biomarker-based ELISAs for the detection of animals with focal lesions and any type of lesions.
| METHOD | AUC | P value | CUT OFF | SE (%) | SP (%) | DV |
|---|---|---|---|---|---|---|
| DETECTION OF ANIMALS WITH FOCAL LESIONS | ||||||
| ABCA13 ELISAa | 0.837 | <0.001 | 1.74 | 79.25 | 88.06 | 0.837 |
| MMP8 ELISA | 0.771 | <0.001 | 33.31 | 87.27 | 64.18 | 0.757 |
| SPARC ELISA | 0.802 | <0.001 | 273.15 | 59.26 | 86.57 | 0.729 |
| IDEXX ELISAb | 0.541 | 0.434 | 28.39 | 14.55 | 100.00 | 0.573 |
| IDEXX ELISAc | 55.00 | 5.45 | 100.00 | 0.527 | ||
| Fecal culture | 5.45 | 100.00 | 0.527 | |||
| Fecal PCR | 9.09 | 100.00 | 0.545 | |||
| Tissue culture | 28.30 | 100.00* | 0.642 | |||
| Tissue PCR | 28.30 | 100.00* | 0.642 | |||
| DETECTION OF ANIMALS WITH ANY LESION | ||||||
| ABCA13 ELISAa | 0.793 | <0.001 | 1.39 | 69.41 | 86.57 | 0.780 |
| MMP8 ELISA | 0.775 | <0.001 | 33.17 | 87.50 | 64.18 | 0.758 |
| SPARC ELISA | 0.777 | <0.001 | 291.55 | 51.72 | 88.06 | 0.699 |
| IDEXX ELISAb | 0.618 | 0.012 | 28.39 | 28.41 | 100.00 | 0.642 |
| IDEXX ELISAc | 55.00 | 21.59 | 100.00 | 0.608 | ||
| Fecal culture | 11.36 | 100.00 | 0.557 | |||
| Fecal PCR | 25.00 | 100.00 | 0.625 | |||
| Tissue culture | 38.37 | 100.00* | 0.692 | |||
| Tissue PCR | 39.53 | 100.00* | 0.698 | |||
AUC, area under the curve; P-value, it is the p-value of the AUC area, indicates whether the discrimination between animals with focal, multifocal, diffuse or any type of lesions and controls is significant; The cut-off point is expressed as ng/mL for the biomarkers and as a % of the positive reference sample for the IDEXX ELISA; SE, sensitivity; SP, specificity; DV, diagnostic value (semi-sum of the sensitivity and specificity); The control group consists of 67 animals, 6 animals with no lesions detected and 61 from a PTB-free farm; ABCA13, bovine ATP binding cassette subfamily A member 13; a, indicate that the number of animals with focal, multifocal, diffuse or with any type of lesions analysed for ABCA13 was 53, 17, 15 and 85, respectively; b, the cut off value used to estimate the sensitivity and specificity of the assay was calculated by ROC analysis; c, the cut off value used to estimate the sensitivity and specificity of the assay was the one established by the supplier
*, the estimation of the specificity for this methods is based on the analysis of 6 animals with no lesions, there is not availability of tissues for the 61 live animals from the PTB-free farm. The diagnostic methods with the best diagnostic value are shown in bold face.