Sweat testing practice in Swiss hospitals

To determine whether the current practice of sweat testing in Swiss hospitals is consistent with the current international guidelines.

A questionnaire was mailed to all children's hospitals (n = 8), regional paediatric sections of general hospitals (n = 28), and all adult pulmonology centres (n = 8) in Switzerland which care for patients with cystic fibrosis (CF). The results were compared with published "guidelines 2000" of the American National Committee for Clinical Laboratory Standards (NCCLS) and the UK guidelines of 2003.

The response rate was 89%. All 8 children's hospitals and 18 out of 23 answering paediatric sections performed sweat tests but none of the adult pulmonology centres. In total, 1560 sweat tests (range: 5-200 tests/centre/year, median 40) per year were done. 88% (23/26) were using Wescor systems, 73% (19/26) the Macroduct system for collecting sweat and 31% (8/26) the Nanoduct system. Sweat chloride was determined by only 62% (16/26) of all centres; of these, only 63% (10/16) indicated to use the recommended diagnostic chloride-CF-reference value of >60 mmol/l. Osmolality was measured in 35%, sodium in 42% and conductivity in 62% of the hospitals. Sweat was collected for maximal 30-120 (median 55) minutes; only three centres used the maximal 30 minutes sample time recommended by the international guidelines.

Sweat testing practice in Swiss hospitals was inconsistent and seldom followed the current international guidelines for sweat collection, analyzing method and reference values. Only 62% were used the chloride concentration as a diagnostic reference, the only accepted diagnostic measurement by the NCCLS or UK guidelines.