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Table 3 Test-duration and provocation-doses of methacholine (mg) needed to achieve the different provocation-dose levels

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

Comparison of average test-duration until different PD-levels reached
  Number Mean SD Lower 95%CL Upper 95%CL
PD40 sGeff 484 14:45 05:54 14:15 15:14
PD20 FEV1 484 17:46 05:16 17:18 18:14
PD20 FEF50 484 16:17 05.36 15:47 16:47
Test-duration: sGeff < FEV1; sGeff < FEF50; FEF50 < FEV1 (p<0.001)
Provocation-doses of methacholine (mg) needed to reach the different PD levels
PD40 sGeff
AHR 409 .495 .491 .447 .543
No AHR 75 2.185 .059 2.17 2.197
PD20 FEV1
AHR 176 .739 .615 .647 .830
No AHR 243 2.189 .044 2.183 2.194
PD-level not reached 65 .873 .450 .761 .985
PD20 FEF50
AHR 307 .625 .588 .559 .691
No AHR 146 2.188 .046 2.180 2.195
PD-level not reached 31 .936 .496 .754 1.117
Comparison between the 3 test procedures assessed by summary independent sample t-test
  mean diff. SE t Significance
PD40 sGeff versus PD20 FEV1 .244 .048 5.088 p<.000
PD40 sGeff versus PD20 FEF50 .130 .040 3.223 p=.001
PD20 FEV1 versus PD20 FEF50 .114 .056 2.011 p=.045