Table 3.
Diagnostic test characteristics for serum total protein concentration (STP) in both normohydrated and dehydrated patients and gamma-glutamyl-transferase activity (GGT) in calves with age > 3 days for assessing the failure of transfer of passive immunity in 72 diarrheic Holstein Friesian calves using three different cut-off points (serum immunoglobulin G concentration 10 g/L, 18 g/L, and 25 g/L)
| Cut-off value for diagnosing FTPI | Classification variable | N | Se (%) (CI 95%) | Sp (%) (CI 95%) | PPV (%) (CI 95%) | NPV (%) (CI 95%) | Acc (%) (CI 95%) |
|---|---|---|---|---|---|---|---|
| IgG 10 g/L | STP in normohydrated calves | 18 | 100.0 (54.1–100.0) | 75.0 (42.8–94.5) | 66.7 (42.9–84.2) | 100.0 | 83.3 (58.6–96.4) |
| STP in dehydrated calves | 54 | 75.0 (47.6–92.7) | 84.2 (78.7–94.0) | 66.7 (47.7–81.5) | 88.9 (77.2–95.0) | 81.5 (68.6–90.8) | |
| GGT in calves with age > 3 gg | 61 | 94.7 (74.0 -99.9) | 83.3 (68.6–93.0) | 72.0 (56.5–83.6) | 97.2 (83.8–99.6) | 85.3 (73.8–93.0) | |
| GGT in normohydrated calves > 3 days | 15 | 100.0 (47.8–100.0) | 90.0 (55.5–99.7) | 83.3 (43.8–97.0) | 100.0 | 93.3 (68.1–99.8) | |
| GGT in dehydrated calves > 3 days | 46 | 100.0 (76.8–100.0) | 87.5 (71.0 -96.5) | 77.8 (58.3–89.7) | 100.0 | 91.3 (79.2–97.6) | |
| IgG 18 g/L | STP in normohydrated calves | 18 | 75 (42.8–94.5) | 100.0 (54.1–100.0) | 100.0 | 66.7 (42.9–84.2) | 83.3 (58.6–96.4) |
| STP in dehydrated calves | 54 | 74.3 (56.7–87.5) | 63.2 (38.4–83.7) | 78.8 (66.6–87.4) | 57.1 (40.8–72.1) | 70.4 (56.4–82.0) | |
| GGT in calves with age > 3 gg | 61 | 70.3 (53.0 -84.1) | 87.5 (67.6–97.3) | 89.7 (74.7–96.2) | 65.6 (53.2–76.2) | 77.1 (64.5–86.9) | |
| GGT in normohydrated calves > 3 days | 15 | 66.7 (29.9–92.5) | 100.0 (54.1–100) | 100.0 | 66.7 (44.3–83.4) | 80.0 (51.9–95.7) | |
| GGT in dehydrated calves > 3 days | 46 | 71.43 (51.3–86.8) | 83.3 (58.6–96.4) | 87.0 (69.8–95.1) | 65.2 (50.2–77.7) | 76.1 (61.2–87.4) | |
| IgG 25 g/L | STP in normohydrated calves | 18 | 100.0 (79.4–100.0) | 100.0 (15.8–100.0) | 100.0 | 100.0 | 100.0 (81.5–100.0) |
| STP in dehydrated calves | 54 | 93.0 (80.9–98.5) | 45.5 (16.7–76.6) | 87.0 (79.4–92.0) | 62.5 (31.9–85.6) | 83.3 (70.7–92.1) | |
| GGT in calves with age > 3 gg | 61 | 58.3 (43.2–72.4) | 92.3 (64.0 -99.8) | 96.6 (80.8–99.5) | 37.5 (29.3–46.5) | 65.6 (52.3–77.3) | |
| GGT in normohydrated calves > 3 days | 15 | 61.5 (31.6–86.1) | 100 (15.8–100) | 100 | 28.6 (16.7–44.3) | 66.7 (38.4–88.2) | |
| GGT in dehydrated calves > 3 days | 46 | 62.9 (44.9–78.5) | 90.9 (58.7–99.8) | 95.7 (76.9–99.3) | 43.5 (32.5–55.2) | 69.6 (54.3–82.3) |
N, number of calves; Se, sensitivity; Sp, specificity; PPV, positive predictive value; NPV, negative predictive value; CI 95%, 95% confidence interval; Acc, accuracy