AShort Protocol forMethacholine Provocation Testing Adapted tothe Rosenthal-Chai Dosimeter Technique*

Background: Thepurpose ofthisstudy was todevelop arapid andsafe methacholine provocation protocol equivalent tothestandard dosimeter technique. Methods: Therapid protocol comprised ashort andalong subprotocol. Thechallenge was started with one ofthesesubprotocols according tothesubject's answers toaquestionnaire andbaseline lung function. IfFEVXdropped by10%during theshortsubprotocol, thetest was continued with thelong subprotocol. Theconcentrations ofmethacholine andnumbers ofinhalations were chosen tomatchtheconcentrations ofthestandard method asclosely aspossible. Toverify the protocol, we compared bothmethods in38subjects withasthma and10control subjects. Results: Theprovocative concentrations ofmethacholine (PC2QFEV!) obtained withthestandard method andtherapid method were within one doubling concentration in38of40subjects. None ofthesubjects whowere normoreactive according tothestandard method(PC20FEV! >8mg/mL) responded intherapid protocol. Thestandard methodrequired, on average (±SD), 34±11min; therapid methodrequired 15±3min. Conclusions: Therapid provocation protocol isequivalent tothestandard method, without loss in precision andsafety, butwithconsiderable saving intime.Therefore, itappears tobeparticularly suited forstudies thatrequire comparability withprovocative concentrations obtained withthe Rosenthal-Chai dosimeter method. (CHEST 1997; 111:866-69)