Diagnose COPD, if patient has history of ≥1 COPD indications, and has:wheeze – widespread and more on expirationon investigation:PEFR during an exacerbation <80%, with minor or no change with bronchodilatorother supporting/ indicative investigations:blood CP (to check for anemia and polycythemia, if required)chest X-rays (vertical heart, hyperinflated lungs, low-set diaphragm). Here, CP is linked to polycythemia.