title: Lack of harmonization in sweat testing for cystic fibrosis - a national survey.
abstract: BACKGROUND
  Sweat testing is used in the diagnosis of cystic fibrosis. Interpretation of the sweat test depends, however, on the method performed since conductivity, osmolality and chloride concentration all can be measured as part of a sweat test. The aim of this study was to investigate how performance of the test is organized in Denmark.
  
  
  METHODS
  Departments conducting the sweat test were contacted and interviewed following a premade questionnaire. They were asked about methods performed, applied NPU (Nomenclature for Properties and Units) code, reference interval, recommended interpretation and referred literature.
  
  
  RESULTS
  14 departments performed the sweat test. One department measured chloride and sodium concentration, while 13 departments measured conductivity. One department used a non-existing NPU code, two departments applied NPU codes inconsistent with the method performed, four departments applied no NPU code and seven applied a correct NPU code. Ten of the departments measuring conductivity applied reference intervals. Nine departments measuring conductivity had recommendations of a normal area, a grey zone and a pathological value, while four departments only applied a normal and grey zone or a pathological value. Cut-off values for normal, grey and pathological areas were like the reference intervals inconsistent.
  
  
  CONCLUSIONS
  There is inconsistent use of NPU codes, reference intervals and interpretation of sweat conductivity used in the process of diagnosing cystic fibrosis. Because diagnosing cystic fibrosis is a combined effort between local pediatric departments, biochemical and genetic departments and cystic fibrosis centers, a national harmonization is necessary to assure correct clinical use.
authors.affiliation: Department of Clinical Biochemistry and Pharmacology, Odense University Hospital , Denmark.
authors.forename: Anne Lindegaard
authors.initials: AL
authors.lastname: Christiansen
authors.forename: Mads
authors.initials: M
authors.lastname: Nybo
mesh_terms: D002712:Chlorides / Q000378:metabolism*; D019963:Clinical Chemistry Tests / Q000592:standards; D003550:Cystic Fibrosis / Q000175:diagnosis* / Q000378:metabolism; D003718:Denmark; D019538:Health Care Surveys; D006801:Humans; D012015:Reference Standards; D012016:Reference Values; D011795:Surveys and Questionnaires; D013542:Sweat / Q000378:metabolism*
chemical_list: D002712:Chlorides
keywords: Chlorides; cystic fibrosis; diagnosis; screening and sweat