Section 296-20-385 - Categories of persisting variable respiratory impairment with normal baseline spirometry(1) "Normal" bronchial reactivity is demonstrated by an insignificant (less than twenty percent) fall from baseline FEV1 at test doses of histamine or methacholine, up to 16 mg/ml (continuous inhalation method) or up to 160 breath units (cumulative, repeated deep breath technique).(2) "Mild" bronchial hyperactivity (BHR) is a significant (equal to or greater than twenty percent) fall in the FEV1 at test doses of 2.1-16 mg/ml, or 21-160 breath units.(3) "Moderate" BHR is a significant (equal to or greater than twenty percent) fall in the FEV1 at test doses of 0.26-2 mg/ml, or 2.6-20 breath units.(4) "Marked" BHR is a significant (equal to or greater than twenty percent) fall in the FEV1 at test doses equal to or less than .25 mg/ml, or 2.5 breath units.Wash. Admin. Code § 296-20-385
Statutory Authority: RCW 51.04.020(4), 51.04.030 and 51.32.080(2). 94-03-073, § 296-20-385, filed 1/17/94, effective 3/1/94.