A negative inhalational methacholine challenge as defined bv the absence of a 20% decrease in FEV(1), at a PD(20) dose of >960 micrograms (normal bronchial hyperresponsiveness). Methacholine challenge testing will not be performed if the subject has a history of allergy to methacholine. Results of testing performed by the subject's primary care provider may be accepted as evidence of a negative methacholine challenge.