Sweat test for the diagnosis of fibrocystic disease of the pancreas; report of a fatality.

The recognition of the electrolyte disturbance in the sweat of patients with fibrocystic disease by Darling, diSant' Agnese, Perera and Andersen (1953) led Shwachman, Leubner and Catzel (1955) to devise a simplified method of obtaining sweat for biochemical assay. In this method the patient is placed in a plastic bag up to the neck and covered with a blanket, the sweat being collected in a weighed square of gauze which is covered with a piece of impermeable sheeting and strapped to the back. The recommended time is 30-90 min., depending on the rate of sweating. The test is now widely used. In spite of the theoretical risks no serious ill effects from it have been reported. We have had the unfortunate experience of a death following its use, which we record as a reminder of its potential danger.