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. 2021 Aug 19;13(8):1651. doi: 10.3390/v13081651

Table 2.

Diagnostic sensitivity and other accuracy measures of rNP I-ELISA for the detection of anti-IgG RVFV antibody in domestic ruminants from RVF-endemic countries using different cut-off values.

Animal
Species		 Cut-Off
PP Value 1 		FN 2/TP 3 D-Se 4
(95% CI) 5 		Ef 6 Y 7 PPV 8
(%)		 NPV 9
(%)
Sheep
Mean + 2SD 10 18.63 1/274 99.6 (98–100) 0.964 0.953 83.80 99.91
Mean + 3SD 11 23.30 2/273 99.3 (97.4–99.9) 0.963 0.976 91.75 99.86
TG-ROC 12 31.23 7/268 97.5 (94.8–99) 0.960 0.970 97.12 99.57
Goats
Mean + 2SD 19.28 0/369 100 (99–100) 0.967 0.952 86.82 100.00
Mean + 3SD 24.17 0/369 100 (99–100) 0.966 0.978 92.62 100.00
TG-ROC 26.57 0/369 100 (99–100) 0.966 0.988 95.63 100.00
Cattle
Mean + 2SD 24.38 15/341 95.8 (93.1–97.6) 0.957 0.921 88.65 98.70
Mean + 3SD 30.86 33/323 90.7 (87.2–93.5) 0.948 0.894 94.22 97.85
TG-ROC 30.46 33/323 90.7 (87.2–93.5) 0.947 0.893 93.86 97.82

1 Percentage positivity of the positive internal control serum; 2 False negative; 3 True positive; 4 Diagnostic sensitivity; 5 Confidence intervals; 6 Efficiency; 7 Youden’s index; 8 Positive predictive value;9 Negative predictive value; 10 Cut-off value determined as mean + 2 standard deviations of PP values in VNT-negative animals; 11 Cut-off value determined as mean + 3 standard deviations of PP values in VNT-negative animals; 12 Cut-off value determined by the two-graph receiver operating characteristic analysis in ruminant serum panels from RVF-endemic countries.