Sweat tests to diagnose cystic fibrosis in adults.
Twenty five patients with cystic fibrosis and 25 controls were studied to define a sweat sodium concentration in adults that could be taken as diagnostic of cystic fibrosis. Some of the controls had a sweat sodium concentration of over 50 mmol(mEq)/l, and thus cystic fibrosis should be diagnosed in an adult only when two measurements of sweat sodium concentration are above 70 mmol/l. In cases in which the sweat sodium concentration was borderline a suppression test using fludrocortisone improved the accuracy of diagnosis; this test entails recording the lowest concentration reached after administration of the drug. A scatter diagram of the baseline sweat sodium concentrations plotted against the lowest concentration attained after suppression with fludrocortisone may aid the diagnosis further.
D000293:Adolescent; D000328:Adult; D003550:Cystic Fibrosis / Q000175:diagnosis* / Q000378:metabolism; D005260:Female; D005438:Fludrocortisone; D006801:Humans; D008297:Male; D012016:Reference Values; D012964:Sodium / Q000032:analysis*; D013542:Sweat / Q000032:analysis*
D012964:Sodium; D005438:Fludrocortisone