SWEAT TESTING: RECOMMENDATIONS FOR THE PERFORMANCE AND INTERPRETATION OF RESULTS OF THE ITALIAN CYSTIC FIBROSIS SOCIETY

Key words: Sweat test, Cystic fibrosis, Italian recommendations

The quantitative measurement of sweat electrolytes following stimulation by pilocarpine iontophoresis remains the gold standard for the diagnosis of both classical, atypical forms of CF and the so called CF related diseases also in the genomic era. In fact, despite the discovery of over 1000 mutations in the cystic fibrosis transmembrane conductance regulator gene on chromosome 7, a minority of children with cystic fibrosis have no identifiable gene mutations. Moreover a number of mutations are associated with atypical and very mild clinical manifestations and with intermediate or negative sweat test results. With the introduction of routine neonatal screening programs accurate analysis of sweat test electrolytes is particularly important. The recent first national audit in Italy showed widely variable practice and standards in sweat testing and identified inconsistencies between current practices and international guidelines. The Italian Cystic Fibrosis Society suggested that recommendations were needed and a multidisciplinary working group was created. This group was composed by various experts in medical and laboratory disciplines (chemists, biologist, nurses, clinicians) and representatives of different scientific societies and patients. They develop the document based on evidence-based UK guidelines with contributes from US and Australian guidelines, experts’ opinions and the most recent scientific evidences. Recommendations are graded A, B, or C, depending on the level of evidence. The document covers subject suitability, the methods for stimulations and collection of sweat, the performance and analytical quality control of the test, interpretation of results. It also includes a form for the patient’s information. The full guidelines can be found on: http://www.sifc.it/index.php?option=com_docman&task= cat_view&gid=70&Itemid=125 and http://www.medicoebambino.com/index.php?u= sudore_test_raccomandazioni_fibrosi