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Table 2 Measures of MCH-challenge procedures computed for response characteristics of sGeff, FEV1 and FEF50

From: Diagnostic accuracy of methacholine challenge tests assessing airway hyperreactivity in asthmatic patients - a multifunctional approach

  PD-40sGeff PD-45sGeff PD-50sGeff PD-20FEV1 PD-20FEF50
N 484 484 484 484 484
PD-level not reached (%) 0 (0) 6 (1.2) 16 (3.3) 44 (9.1) 31 (6.4)
Diagnostic accuracy differentiating AHR from non-AHR in all patients but excluding patients not having reached PD-level
n (%) 484 (100) 478 (98.8) 468 (96.7) 440 (90.9) 453 (93.6)
Prevalence 69.6% 69.6% 69.6% 69.6% 69.6%
Sensitivity 93.2% 89.3% 82.8% 54.9% 71.5%
Specificity 35.4% 44.2% 52.4% 85.0% 55.1%
PPV 76.8% 78.6% 79.9% 89.4% 78.5%
NPV 69.3% 64.4% 57.0% 45.1% 45.8%
Diag. Odds Ratio (DOR) [33] 7.473 6.628 5.291 6.915 3.081
 95% CI of DOR 4.347–12.847 4.123–10.655 3.443–8.133 4.189–11.417 2.061–4.605
pos. LR 1.443 1.600 1.739 3.660 1.592
neg. LR 0.192 0.242 0.328 0.531 0.517
Diagnostic effectiveness 0.756 0.756 0.736 0.641 0.665
Cumulative percent-response in all patients (asthmatics and non-asthmatic subjects) at each provocation level n/n (%)
1st PD level (%) 161/484 (42.4) 126/484 (26.0) 94/484 (19.4) 94/484 (9.7) 99/484 (20.5)
2nd PD level (%) 362/484 (74.8) 326/484 (67.4) 296/484 (61.2) 217/484 (44.8) 280/484 (57.9)
3rd PD level (%) 415/484 (85.7) 395/484 (81.6) 376/484 (77.7) 270/484 (55.8) 344/484 (71.1)
No AHR detected 104/484 (21.5) 132/484 (27.3) 164/484 (33.9) 302/484 (62.4) 206/484 (42.6)
  1. PD provocation dose, PPV positive predictive value, NPV negative predictive value, LR likelihood ratio, DOR diagnostic odds ratio [33]