Abstract

The change in transfer coefficient (Kco) with increasing heart rate during exercise was studied in 25 normal subjects and in 21 patients with pulmonary sarcoidosis. The slope of the Kco response against heart rate was found to be 0·0053 mmol min⁻¹ kPa⁻¹ l⁻¹ per beat in the normal group but in many of the patients was two standard deviations or more below this normal slope, even when their routine function tests were normal. This response of Kco to exercise is a more sensitive index of changed function than more routine function tests in pulmonary sarcoidosis.