RT Journal Article SR Electronic T1 When should a methacholine challenge be ordered for a patient with suspected asthma? JF Cleveland Clinic Journal of Medicine JO Cleve Clin J Med FD Cleveland Clinic SP 37 OP 40 VO 75 IS 1 A1 Swartz, Edina A1 Lang, David YR 2008 UL http://www.ccjm.org/content/75/1/37.abstract AB