WBC Cut-off (µl) Sensitivity or True Positive(TP) Specificity or True Negative(TN) False Negative(FN) = 1-Sensitivity False Positive(FP) = 1-Specificity PPV NPV Reduction of Cultures
-1 1 0 0 1 0.5 1 0
10.5 0.913 0.5 0.087 0.5 0.646 0.852 0.293
22.5 0.856 0.615 0.144 0.385 0.69 0.81 0.38
27 0.846 0.654 0.154 0.346 0.71 0.81 0.404
50.5 0.76 0.731 0.24 0.269 0.738 0.752 0.486
105 0.654 0.823 0.346 0.177 0.787 0.704 0.585
200 0.596 0.869 0.404 0.131 0.82 0.683 0.637
322.5 0.481 0.877 0.519 0.123 0.796 0.628 0.698
422 0.423 0.885 0.577 0.115 0.786 0.605 0.731
500 0.375 0.892 0.625 0.108 0.777 0.588 0.759
712.5 0.327 0.908 0.673 0.092 0.78 0.574 0.79
1012 0.298 0.931 0.702 0.069 0.812 0.57 0.816
1581 0.173 0.938 0.827 0.062 0.738 0.532 0.883
2013.5 0.144 0.954 0.856 0.046 0.758 0.527 0.905

Table 4: Summary of Sensitivity, Specificity, Negative Predictive Value, Positive Predictive Value and Reduction of Cultures of UF-1000i according to WBC count cut-off values in 234 specimens