Estimates of sensitivity and specificity for a questionnaire item on cold induced WF
| WF according to the questionnaire | |||||
|---|---|---|---|---|---|
| Diagnosis of WF at the clinical examination | Yes | No | Total | 95% CI | |
| The assessment after clinical examination, including a careful history, was used as the gold standard. | |||||
| In total 806 mechanics had answered the questionnaire (see fig 1). A clinical examination was performed in 187 subjects (of 195) who answered “yes” to the question of whether they had white finger, 103 subjects (of 113) who answered “no”, but who reported numbness (5/103 were diagnosed with white fingers at clinical examination), and in a random sample (n=29) of those 498 subjects (see fig 1) who denied white finger as well as numbness (none had the diagnosis at clinical examination). The figure 596 in the table is derived from 498 + (103 − 5). The total number in the table is 788 instead of 806 owing to the 18 non-attendants. | |||||
| Yes | 138 | 5 | 143 | Sensitivity 97% | 82 to 99 |
| No | 49 | 596 | 645 | Specificity 92% | 90 to 94 |
| Total | 187 | 601 | 788 | ||