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Asbestosis — SCE Respiratory MCQ

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HardOccupational Lung DiseaseAsbestosisSCE Respiratory

Twice-daily peak flows over two weeks in suspected asthma are 420 and 300 L/min on day 1, 390 and 330 on day 2, and 400 and 320 on day 3. Using amplitude percentage mean for each day, which conclusion is supported?

Educational content. Not a substitute for clinical judgement or local policy.

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Correct answer: B — Days 1 and 3 exceed 20%, supporting variable airflow obstruction in the clinical context

Explanation lettering: D = shown as A · E = shown as B · A = shown as C · C = shown as D · B = shown as E

E is correct. Daily amplitude percentage mean is (highest minus lowest) divided by their mean. The values are 120/360 = 33.3%, 60/360 = 16.7%, and 80/360 = 22.2%; therefore days 1 and 3 exceed 20%, whereas day 2 does not. NICE uses PEF variability of 20% or more as objective support for asthma when earlier tests are unavailable or non-diagnostic. The denominator is the mean, a large range is not invalid, and treatment withholding is individualised rather than an absolute four-week prerequisite.

Reference: https://www.nice.org.uk/guidance/ng245/chapter/recommendations