[Detection of bronchial hyperreactivity using the 1-step histamine test]

An attempt was made to establish whether patients with, and those without, bronchial hyperreactivity can be reliably differentiated on the basis of a single-step histamine provocation test. Thirty-five asymptomatic persons (7 normal subjects, 13 patients with a history of coughing and oppressive sensation, and 13 patients with bronchial asthma) inhaled 10 breaths of a 5% histamine solution after a trial run with physiological NaCl solution. SGaw was determined in a volume constant body plethysmograph. The median dose of histamine was 0.51 mg, the sGaw median after inhalation was 0.37 kPa-1s-1. Between the values for sGaw prior to and following inhalation, and the histamine dose, a linear dose response curve was plotted, from which PD25sGaw was interpolated. On the basis of PD25sGaw, patients with bronchial hyperreactivity and normal subjects could be differentiated. At a PD25sGaw threshold value of 0.27 mg, the sensitivity is 0.85 and the specificity 0.86. Thus, the results obtained with single-step histamine provocation are comparable with those obtained with the conventional provocation methods involving increasing concentrations of histamine, and with those of the methacholine single-step provocation challenge.