The use and abuse of office spirometry.

Spirometry programs (outside of primary care settings) designed to detect COPD in the general adult population are not justified, since the true positive yield (airway obstruction with an FEV1 below 60% predicted) is very low, and the false positive rate is very high. However, spirometry is greatly under-utilised by GPs who often prescribe inhalers for patients haphazardly. Inhalers for COPD are expensive and risk serious side-effects, so they should not be prescribed for current or former smokers without confirming severe airway obstruction. A large program in Finland has shown that some GPs can perform good quality spirometry. If good quality spirometry is not available in the GP's office, patients should be referred to a local resource for pre- and post-bronchodilator spirometry. More studies are needed to show that GPs use spirometry results systematically to make decisions which truly benefit their patients with asthma or COPD.