Validity measures for different threshold points for International Severity Score for familial Mediterranean fever (ISSF)
| Score | (TP/FP) | (TN/FN) | Sensitivity (%) | Specificity (%) | PPV (%) | NPV (%) |
|---|---|---|---|---|---|---|
| 0 | 149/0 | 11/121 | 100 | 8 | 55 | 100 |
| 1 or more | 147/2 | 37/95 | 99 | 28 | 61 | 95 |
| 2 or more | 138/11 | 78/54 | 93 | 59 | 72 | 88 |
| 3 or more | 112/37 | 103/29 | 75 | 78 | 79 | 74 |
| 4 or more | 78/71 | 120/12 | 52 | 91 | 87 | 63 |
| 5 or more | 39/110 | 129/3 | 26 | 98 | 93 | 54 |
| 6 or more | 18/131 | 132/0 | 12 | 100 | 100 | 50 |
| 7 or more | 5/144 | 132/0 | 3 | 100 | 100 | 48 |
| 8 or more | 1/148 | 132/0 | 1 | 100 | 100 | 47 |
| 9 or more | 0/149 | 132/0 | 0 | 100 | 0 | 47 |
| 10 | 0/149 | 132/0 | 0 | 100 | 0 | 47 |
FN, false negative; FP, false positive; NPV, probability of true non-severe patients rate according to the ISSF; PPV, probability of true severe patients rate according to the ISSF; sensitivity, detected proportion of true severe patients; specificity, detected proportion of true non-severe patients; TN, true negative; TP, true positive.