Diagnostic criteria for asthma in adults, adolescents, and children 6–11 years
1. HISTORY OF
Wheeze, shortness of breath, chest tightness and cough
• More than one type of respiratory symptom (in adults, isolated cough is seldom due to asthma)
• Symptoms occur variably over time and vary in intensity
• Symptoms are often worse at night or on waking
• Symptoms are often triggered by exercise, laughter, allergens, cold air
• Symptoms often appear or worsen with viral infections
2. CONFIRMED VARIABLE EXPIRATORY AIRFLOW LIMITATION
2.1 Documented* expiratory airflow limitation
At a time when FEV1 is reduced, confirm that FEV1/FVC is reduced compared with lower limit of normal (it is usually >0.75–0.80 in adults, >0.90 in children)
AND
2.2 Documented* excessive variability in lung function* (one or more of the following):
The greater the variations, or the more occasions excess variation is seen, the more confident the diagnosis. If initially negative, tests can be repeated during symptoms or in the early morning.
•Positive bronchodilator (BD) responsiveness (reversibility) test
Adults: increase in FEV1 of >12% and >200 mL (greater confidence if increase is >15% and >400 mL). Children: increase in FEV1 of >12% predicted
Measure change 10–15 minutes after 200–400 mcg salbutamol (albuterol) or equivalent, compared with pre-BD readings. Positive test more likely if BD withheld before test: SABA ≥4 hours, twice-daily LABA 24 hours, once-daily LABA 36 hours
•Excessive variability in twicedaily PEF over 2 weeks
Adults: average daily diurnal PEF variability >10%*
Children: average daily diurnal PEF variability >13%*
•Significant increase in lung function after 4 weeks of anti-inflammatory treatment
Adults: increase in FEV1 by >12% and >200 mL (or PEF† by >20%) from baseline after 4 weeks of treatment, outside respiratory infections
•Positive exercise challenge test Adults: fall in FEV1 of >10% and >200 mL from baseline
Children: fall in FEV1 of >12% predicted, or PEF >15%
•Positive bronchial challenge test
(usually only for adults)
Fall in FEV1 from baseline of ≥20% with standard doses of methacholine, or ≥15% with standardized hyperventilation, hypertonic saline or mannitol challenge
•Excessive variation in lung function between visits (good
specificity but poor sensitivity)
Adults: variation in FEV1 of >12% and >200 mL between visits, outside of respiratory infections
Children: variation in FEV1 of >12% in FEV1 or >15% in PEF† between visits (may include respiratory infections)
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