Use of an open access spirometry service by general practitioners

To understand better which patients with which diagnoses or suspected diagnoses are referred for spirometry in primary care, and to assess whether all such referrals are appropriate.

200 consecutive patient referrals to an open access spirometry service from ten local general practices were evaluated by perusing the request forms, and analysis of the spirometry results and the report sent to the general practitioner (GP).

51% of all referrals had suspected or stated COPD, but airway obstruction was demonstrated in only 53% of cases. A minority had a degree of reversibility which suggested an additional asthma component at least. Airway obstruction was rarely demonstrated in patients referred with stated or suspected asthma. 117 patients were referred with stated or suspected airway disease but had no evidence of airway narrowing on testing. 14.5% of these had an unexpected small lung (restrictive) disorder. Six of these had a BMI of more than 30.

Most referrals with stated or suspected COPD were highly appropriate since spirometry is required in order to establish the correct diagnosis. Referral of patients with suspected asthma is less likely to be helpful, and a period of home peak flow monitoring may be more useful. Restrictive disorders can be confused with airway disorders, and obesity may be underestimated as a cause of breathlessness.