Methacholine PC20: 1-point formula. American College of Allergy, Asthma, & Immunology

摘要

We reexamined methacholine challenges from a previous study of 1,000 randomly selected challenges from the clinical pulmonary function laboratory at the Royal University Hospital in Saskatoon. From the 315 tests with positive results (PC_(20)<=8 mg/mL) we selected all tests (n = 211) in which the last 2 concentrations received were consecutive doubling concentrations (Cl and C2, respectively) and in which the response to the final concentration was greater than 20% (R2) and to the second to the last concentration was less than 20% (Rl).