No of apprentices in the group (%)* | No of apprentices with symptoms at work (n = 45)† | No of apprentices without symptoms at work (n = 251)‡ | Sensitivity (%) | Specificity (%) | PPV (%) | NPV (%) | |
No (%) | No (%) | ||||||
Probability ⩾0.10 | |||||||
Model 1 | 118 (39.9) | 37 (31.4) | 81 (68.6) | 82.2 | 67.7 | 31.4 | 95.5 |
Model 2 | 133 (44.9) | 38 (28.6) | 95 (71.4) | 84.4 | 62.2 | 28.6 | 95.7 |
Model 3 | 143 (48.3) | 38 (26.6) | 105 (73.4) | 84.4 | 58.2 | 26.6 | 95.4 |
Model 4 | 124 (41.9) | 37 (29.8) | 87 (70.2) | 82.2 | 65.3 | 29.8 | 95.3 |
Probability ⩾0.20 | |||||||
Model 1 | 118 (39.9) | 37 (31.4) | 81 (68.6) | 82.2 | 67.7 | 31.4 | 95.5 |
Model 2 | 92 (31.1) | 33 (35.9) | 59 (64.1) | 73.3 | 76.5 | 35.9 | 94.1 |
Model 3 | 86 (29.1) | 32 (37.3) | 54 (62.8) | 71.1 | 78.5 | 37.3 | 93.8 |
Model 4 | 100 (33.8) | 36 (36.0) | 64 (64.0) | 80.0 | 74.5 | 36.0 | 95.4 |
Probability ⩾0.30 | |||||||
Model 1 | 67 (22.6) | 25 (37.3) | 42 (62.7) | 55.6 | 83.3 | 37.3 | 91.3 |
Model 2 | 67 (22.6) | 25 (37.3) | 42 (62.7) | 55.6 | 83.3 | 37.3 | 91.3 |
Model 3 | 86 (29.1) | 32 (37.3) | 54 (62.8) | 71.1 | 78.5 | 37.3 | 93.8 |
Model 4 | 57 (19.3) | 23 (40.4) | 34 (59.6) | 51.1 | 86.5 | 40.4 | 90.8 |
*Proportion of all apprentices (n = 296).
†Proportion of apprentices with symptoms at work within the probability group.
‡Proportion of apprentices without symptoms at work within the probability group.
Model 1, questionnaire alone; model 2, questionnaire and SPT (skin-prick testing); model 3, questionnaire and BR (bronchial responsiveness to methacholine) testing; model 4, questionnaire, SPT and BR testing; NPV, negative predicted value; PPV, positive predictive value.