Table 2.
Sensitivity (Se), specificity (Sp), Youden index, positive predictive value (PPV), and negative predictive value (NPV) for different MilkoScan FT-plus cut-off values compared with values of 50 g/L of IgG in bovine colostrum (n = 54) and 20 g/L of IgG in ovine colostrum (n = 39), measured by RID assay (gold standard test).
| Species | Cut-Point Value, % Proteins by FT-IR | Se, % (95% CI) |
Sp, % (95% CI) |
Youden Index 1 |
PPV % 2 |
NPV % 3 |
|---|---|---|---|---|---|---|
| Bovine | 8.40% | 100 (87.50–100) |
85.20 (67.50–94.1) |
0.852 | 87.11 | 100 |
| 10.10% | 96.30 (81.70–99.30) |
88.90 (71.90–96.10) |
0.852 | 89.66 | 96.00 | |
| 10.70% | 92.60 (76.60–97.90) |
88.90 (71.90–96.10) |
0.815 | 89.30 | 92.30 | |
| 12.00% | 88.90 (71.90–96.10) |
96.30 (81.70–99.30) |
0.852 | 96.00 | 89.66 | |
| 12.80% | 88.90 (71.90–96.10) |
100 (87.50–100) |
0.889 | 100 | 90.01 | |
| 14.40% | 81.50 (63.30–91.80) |
100 (87.50–100) |
0.815 | 100 | 84.39 | |
| Ovine | 7.90% | 100 (88.60–100) |
77.80 (45.30–93.70) |
0.778 | 65.88 | 100 |
| 8.60% | 96.70 (83.30–99.40) |
88.90 (56.50–98.00) |
0.856 | 98.43 | 78.87 | |
| 9.00% | 96.70 (83.30–99.40) |
100 (70.10–100) |
0.967 | 100 | 98.61 | |
| 9.30% | 90.00 (74.40–96.50) |
100 (70.10–100) |
0.90 | 100 | 95.89 | |
| 9.70% | 80.00 (62.70–90.50) |
100 (70.10–100) |
0.80 | 100 | 92.11 |
Positive value is detection of <50 g of IgG/L in bovine colostrum samples and <20 g of IgG/L in ovine colostrum samples. 1 Youden index = [(Se + Sp)/100] − 1. 2 PPV = positive predictive value. 3 NPV = negative predictive value.