Document Detail

A reference interval for sweat chloride in infants aged between five and six weeks of age.
MedLine Citation:
PMID:  19103961     Owner:  NLM     Status:  MEDLINE    
BACKGROUND: This study was designed to establish a reference interval for sweat chloride for infants without evidence of cystic fibrosis (CF), aged between 5 wk and 6 wk, a time when sweat testing is an integral part of newborn screening for CF. In addition, we compared the gold standard method of sweat testing (quantitative pilocarpine iontophoresis [QPIT, coulometry]) with an emerging methodology (Macroduct [ISE]). METHODS: This was a prospective study on healthy infants at 5-6 wk of age. Sweat collection was undertaken at home on both outer thigh areas using two methods (QPIT and Macroduct ). The order of testing was randomly assigned. Filter paper samples (QPIT) were analysed using flame photometry and coulometry. Macroduct samples were analysed using ion-selective electrodes (ISE, Abbott Architect c8000, UK). RESULTS: Insufficient sweat was collected on 28 occasions with the QPIT (coulometry) method and on 31 with the Macroduct (ISE) capillary system. We achieved a 92% success rate in undertaking two sweat collections consecutively (n = 177). Sweat chloride concentrations were normally distributed with excellent limits of agreement between the two methods of sweat collection and analysis (n = 150). Median (IQR) sweat chloride was 11.2 mmol/L (8-13) with QPIT (coulometry) method with a 99.5th centile (n = 165) of 24 mmol/L. CONCLUSION: The Macroduct (ISE) capillary sweat collection system is valid in this age group. Sweat chloride concentrations above 30 mmol/L should prompt assessment in a specialist CF centre.
Rajamanickam Jayaraj; Paul V Barton; Paul Newland; Roger Mountford; Nigel J Shaw; Emma McCarthy; David M Isherwood; Kevin W Southern
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Annals of clinical biochemistry     Volume:  46     ISSN:  0004-5632     ISO Abbreviation:  Ann. Clin. Biochem.     Publication Date:  2009 Jan 
Date Detail:
Created Date:  2008-12-23     Completed Date:  2009-03-31     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0324055     Medline TA:  Ann Clin Biochem     Country:  England    
Other Details:
Languages:  eng     Pagination:  73-8     Citation Subset:  IM    
Institute of Child Health, University of Liverpool, Liverpool, UK.
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MeSH Terms
Chlorides / analysis*
Infant, Newborn
Prospective Studies
Reference Values
Sweat / chemistry*
Reg. No./Substance:

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