Table 3

Short term (less than 4 months) repeatability of BHR in studies published from 1993 to 2001

Year and source	Participants	Age range (years)	Provocation agent and maximum concentration/cumulative dose	Time interval	Summary statistic	Within person SD (doubling doses or concentrations)	Between person SD (doubling doses or concentrations)	Intraclass correlation coefficient (ICC)
*Estimated from graphical information.
SD, standard deviation.
1993²¹	14 asthmatic patients	19–65	Histamine, 6.9 μmol	1 day	PD₁₅-FEV₁	0.4*	1.8*	0.95
1993²²	20 asthmatic patients	18–65	Methacholine, 32.65 μmol	Within 10 days	PD₂₀-FEV₁	0.6	2.0*	0.92*
1995²⁶	19 asthmatic patients	18–45	Methacholine, 32.65 μmol	1 day	log PD₂₀-FEV₁	0.8*	2.7*	0.92*
1995²⁷	10 non-smoking asthmatic patients	18–57	Histamine, 1.4 μmol	2–7 days	log PD₂₀-FEV₁	0.6	1.1	0.81
1996²⁹	11 asthmatic “hyperresponsive” patients	19–62	Methacholine, 35.2 μmol	1–7 days	log PD₂₀-FEV₁	0.4	1.1*	0.87*
2001³¹	34 non-asthmatic	17–78	Methacholine, 64 mg/ml	Within 3 weeks	log PC₂₀-FEV₁	0.7*	1.4*	0.71*