Table 4.
Contingency tables and performance of the 14-3-3 test according to the initial clinical classification
| Initial diagnosis | |||||||
| Probable CJD, i n= 115 | Possible CJD, i n= 73 | non-sCJD, i n= 484 | |||||
| Final diagnosis | sCJD f | non-sCJD f | sCJD f | non-sCJD f | sCJD f | non-sCJD f | |
| 14-3-3 result | Pos. | 90 [36] | 2 | 56 [27] | 2 | 9 [4] | 11 |
| Neg. | 17 [7] | 6 | 5 [1] | 10 | 0 | 464 | |
| Performance values (%) | |||||||
| PPV | 97.8 (91.6–99.6) | 96.5 (87.0–99.4) | 45.0 (23.8–68.0) | ||||
| NPV | 26.1 (11.1–48.7) | 66.6 (38.7–87.0) | 100 (99.0–100.0) | ||||
| Sensitivity | 84.1 (75.5–90.2) | 91.8 (81.2–96.9) | 100 (62.9–100.0) | ||||
| Specificity | 75.0 (35.5–95.5) | 83.3 (50.9–97.1) | 97.7 (95.8–98.8) | ||||
| Efficiency | 83.5 (75.6–89.3) | 90.4 (81.3–95.6) | 97.7 (95.9–98.8) | ||||
| Prevalence | 93.0 (86.7–96.7) | 83.6 (73.3–90.5) | 1.9 (0.9–3.6) | ||||
sCJDf includes both probable (WHO's criteria without the inclusion of the 14-3-3 test results) and definite cases at final diagnosis. Definite cases are shown in square brackets. Confidence intervals at 95% level are shown in parentheses.