Diagnose asthma, if patient has history of ≥1 asthma indications, and during an exacerbation has: wheeze (widespread and more on expiration)on investigation (may be normal):PEFR during an exacerbation <80% which improves with bronchodilatorother supporting/ indicative investigations:blood CP (eosinophil >5%, though also in bronchitis and COPD)chest X-rays (not usually indicated; may be normal, may be hyperinflation). Here, CP is linked to chronic obstructive pulmonary disease.