שאלה משלב א׳ ברפואה תעסוקתית · מועד 2020, שאלה 78

Correct: D — a fall of 20% in FEV1. That is the accepted threshold for a positive bronchial challenge. Option A requires a fall in both FEV1 and FVC; option B uses a 12% fall in FVC, which is the reversibility criterion rather than a challenge threshold; option C accepts any fall at all, which is within measurement variability.

מקור: לאדו ch.17, עמ ' 256 - INHALATION CHALLENGE TESTS