Abstract
Background:
There are several complementary English-language guidelines for the performance of the sweat chloride test. These guidelines also incorporate information for the collection of conductivity samples. However, recommendations for the measurement and reporting of sweat conductivity are less clear than for sweat chloride. The aim of the study was to develop an understanding of the testing and reporting practices of sweat conductivity in Australasian laboratories.
Methods:
A survey specifically directed at conductivity testing was sent to the 12 laboratories registered with the Royal College of Pathologists of Australasia Quality Assurance Programs.
Results:
Nine (75%) laboratories participated in the survey, seven of whom used Wescor Macroduct® for collecting sweat and the Wescor SWEAT·CHEK™ for conductivity testing, and the remaining two used the Wescor Nanoduct®. There was considerable variation in frequency and staffing for this test. Likewise, criteria about which patients it was inappropriate to test, definitions of adequate collection sweat rate, cutoffs and actions recommended on the basis of the result showed variations between laboratories.
Conclusions:
Variations in sweat conductivity testing and reporting reflect many of the same issues that were revealed in sweat chloride test audits and have the potential to lead to uncertainty about the result and the proper action in response to the result. We recommend that sweat testing guidelines should include clearer statements about the use of sweat conductivity.
Acknowledgments
We wish to thank Mr Peter Graham and Ms Samantha Shepherd for their assistance in reviewing the data in this manuscript.
Author contributions: All the authors have accepted responsibility for the entire content of this submitted manuscript and approved submission.
Research funding: None declared.
Employment or leadership: None declared.
Honorarium: None declared.
Competing interests: The funding organisation(s) played no role in the study design; in the collection, analysis and interpretation of data; in the writing of the report; or in the decision to submit the report for publication.
References
1. Gibson LE, Cooke RE. A test for concentration of electrolytes in sweat in cystic fibrosis of the pancreas utilising pilocarpine by iontophoresis. Pediatrics 1959;23:546–9.Search in Google Scholar
2. Sweat Testing: Sample Collection and Quantitative Chloride Analysis; Approved Guideline – 3rd ed. CLSI document C34-A3. Wayne: PA. Clinical and Laboratory Standards Institute, 2009.Search in Google Scholar
3. Guidelines for the Performance of the Sweat Test for the Investigation of Cystic Fibrosis in the UK, v2 2014. See http://www.acb.org.uk/docs/default-source/committees/scientific/guidelines/acb/sweat-guideline-v2-1.pdf. Accessed 12 Jun 2017.Search in Google Scholar
4. Coakley J, Scott S, Doery J, Greaves R, Talsma P, Whitham E, et al. Australian guidelines for the performance of the sweat test for the diagnosis of cystic fibrosis. Clin Biochem Rev 2006;27(Suppl i):S1–7.Search in Google Scholar
5. Mackay R, George P, Kirk J. Sweat testing for cystic fibrosis: a review of New Zealand Laboratories. J Paediatr Child Health 2006;42:160–4.10.1111/j.1440-1754.2006.00822.xSearch in Google Scholar
6. Barben J, Casaulta C, Spinar R, Schoni M, Swiss Working Group for Cystic Fibrosis (SWGCF). Sweat testing in Swiss hospitals. Swiss Med Wkly 2007;137:192–8.Search in Google Scholar
7. Cirilli N, Padoan R, Raia V, ICFS Sweat Test Working Group. Audit of sweat testing: a first report from Italian Cystic Fibrosis Centres. J Cystic Fibrosis 2008;7:415–22.10.1016/j.jcf.2008.03.005Search in Google Scholar
8. ELITechGroup Biomedical Systems (Formerly Wescor). See https://www.elitechgroup.com/. Accessed 12 Jun 2017.Search in Google Scholar
9. Hammond KB, Turcias NL, Gibson LE. Clinical evaluation of the Macroduct sweat collection system and conductivity analyser in the diagnosis of Cystic Fibrosis. J Pediatr 1994;124:255–60.10.1016/S0022-3476(94)70314-0Search in Google Scholar
10. Kirk JM. Inconsistencies in sweat testing in UK laboratories. Arch Dis Child 2000;82:425–7.10.1136/adc.82.5.425Search in Google Scholar PubMed PubMed Central
11. Coakley J, Scott S, Mackay R, Greaves R, Jolly L, Massie J, et al. Sweat testing for cystic fibrosis: standards of performance in Australasia. Ann Clin Biochem 2009;46:332–7.10.1258/acb.2009.009023Search in Google Scholar PubMed
12. SWEAT·CHEK™ Sweat conductivity analyser. Model 3120 Instruction/Service Manual M2672-2A 2005. See www.wescor.com/translations/Translations?2672-2A.pdf. Accessed 12 Jun 2017.Search in Google Scholar
13. Nanoduct®. Neonatal Sweat Analysis System. Instruction/Service Manual 57-0003-01A 2006. See www.wescor.com/translations/Translations/57-0003-01A.pdf. Accessed 12 Jun 2017.Search in Google Scholar
14. Macroduct® Sweat Collection System instruction/service manual. Model 3700 SYS. M 2551-7 rev A 2004. See www.wescor.com/translations/Translations/M2551-7A-EN.pdf. Accessed 12 Jun 2017.Search in Google Scholar
15. International Standard. ISO 15189:2012. Medical laboratories – Requirements for quality and competence.Search in Google Scholar
©2018 Walter de Gruyter GmbH, Berlin/Boston
