Sweat testing for cystic fibrosis: A review of New Zealand laboratories.
BACKGROUND
Evolving diagnostic criteria for cystic fibrosis, broadening of the populations being tested and the need to interpret intermediate sweat test results have imposed a much greater need to standardize the collection and analysis of sweat.


OBJECTIVE
To identify variations in sweat testing in New Zealand laboratories and compare these with guidelines from the UK and the USA.


METHODS
All laboratories in New Zealand offering sweat testing were identified and data collected from these laboratories by structured questionnaire.


RESULTS
There were no New Zealand laboratories that conformed to either set of guidelines. Inconsistencies were observed in minimum sweat quantities, the nature of the iontophoresis solution, the sweat electrolytes analysed, quoted reference ranges and recommendations made as a consequence of the result.


CONCLUSIONS
Conformity to the guidelines would help to minimize variation in sweat testing in New Zealand. Performance of a sufficient number of tests to maintain expertise is critical, but geographical constraints make patient travel to distant centres difficult in a small, scattered population. A possible solution, where numbers permit, may be the collection of sweat locally, with referral to a major laboratory for analysis. This is only possible with adequate training in collection and follow-up audit of the sweat testing procedure both in the collection and in the analytical phase.
Mackay
Richard
R
Clinical Biochemistry Unit, Canterbury Health Laboratories, Christchurch, New Zealand. richard.mackay@cdhb.govt.nz
George
Peter
P
Kirk
Jean
J
D002624:Chemistry, Clinical; D002712:Chlorides / Q000032:analysis; D019963:Clinical Chemistry Tests / Q000592:standards*; D003550:Cystic Fibrosis / Q000175:diagnosis*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007753:Laboratories / Q000592:standards*; D009520:New Zealand; D017410:Practice Guidelines as Topic; D011786:Quality Control; D012964:Sodium / Q000032:analysis*; D011795:Surveys and Questionnaires; D013542:Sweat / Q000737:chemistry*; D006113:United Kingdom; D014481:United States
D002712:Chlorides; D012964:Sodium