distinguishing asthma and COPD

Last reviewed 11/2019

Distinguishing COPD form asthma is mostly carried out on the basis of patient history and examination. The following features should be used to differentiate the two conditions whenever possible (1):

  COPD Asthma
smoker or ex-smoker nearly all Possibly
symptoms under age of 35 rare often
chronic productive cough common uncommon
breathlessness persistent and progressive variable
night time waking with breathlessness and/or wheeze uncommon common
significant diurnal or day to day variability of symptoms uncommon common


In case of a diagnostic doubt the following can be done to differentiate between the two conditions:

  • serial domiciliary peak flow measurements
    • shows a 20% or greater diurnal or day-to-day variability
  • reversibility test using bronchodilators and corticosteroids can be used to separate asthma patients from those with COPD.
    • a large (> 400 ml) response to bronchodilators
    • a large (> 400 ml) response to 30 mg oral prednisolone daily for 2 weeks


  • 1. National Institute for Health and Clinical Excellence (NICE) 2010. Chronic obstructive pulmonary disease: Management of chronic obstructive pulmonary disease in adults in primary and secondary care.