Abstract | INTRODUCTION: Bronchoprovocation inhalation challenge tests with direct acting stimuli (e.g. methacholine) are widely used clinically to aid in the diagnosis of asthma. Areas covered: The history of direct challenges with histamine and muscarinic agonists is reviewed. This began with parenteral administration of stimuli with responses monitored clinically and by VC, progressing to inhalation dose-response challenges monitored by FEV1 and FEV1/VC ratio, both (the challenge method and the technology to measure FEV1) developed by Robert Tiffeneau in the mid-1940s. Careful standardization of methods has become appreciated albeit after-the-fact. Recent guidelines recommend standardizing the methacholine PD20 at 400 μg above which a methacholine challenge is considered negative. CONCLUSIONS: The methacholine inhalation test is highly sensitive for a diagnosis of current asthma when symptoms under evaluation are clinically current and when methacholine is inhaled without deep inhalations. Under these circumstances, a methacholine PD20 > 400 μg excludes current asthma with reasonable certainty. PD20 values >25 μg and ≤400 μg will have a variable specificity and positive predictive value for asthma which increases the lower the PD20 and the higher the pre-test probability for a diagnosis of asthma. A PD20 ≤25 μg has high specificity and low sensitivity for asthma.
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Authors | Donald W Cockcroft, Beth E Davis, Christianne M Blais |
Journal | Expert review of respiratory medicine
(Expert Rev Respir Med)
Vol. 13
Issue 3
Pg. 279-289
(03 2019)
ISSN: 1747-6356 [Electronic] England |
PMID | 30632426
(Publication Type: Historical Article, Journal Article, Review)
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Chemical References |
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Topics |
- Asthma
(diagnosis)
- Bronchial Provocation Tests
(history, methods)
- History, 20th Century
- History, 21st Century
- Humans
- Methacholine Chloride
- Sensitivity and Specificity
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