title: Sweat-testing in preterm and full-term infants less than 6 weeks of age.
abstract: Our objective was to examine the characteristics of preterm and full-term infants < or = 6 weeks old that influence the success of obtaining sufficient sweat for diagnosis of CF, and corresponding sweat chloride concentrations. A retrospective chart review of 119 sweat tests was performed on 103 preterm and full-term infants < or = 6 weeks of age. Bivariate and multivariate regression analyses were used to determine the predictors of successful sweat testing and characteristics influencing sweat chloride concentrations. Adequate amounts of sweat (> or = 75 mg) were obtained for analysis in 73.8% of initial attempts in the infant group. The following characteristics were associated with increased odds of obtaining a quantity not sufficient (QNS) for sweat chloride concentration measurement: African-American race, infant weight < 2,000 g, preterm birth, and postmenstrual age (PMA) < 36 weeks. With a multivariable logistic model, the only significant predictors were African-American race (7.3, 2.4-21.7) and PMA < 36 weeks (17.9, 4.2-75.9). Sweat chloride concentration in non-CF individuals is inversely related to both gestational age and age at testing, and this effect is additive in a linear regression model. In conclusion, sweat collection can be reliably performed in infants > or = 36 weeks postmenstrual age, > 2,000 g, and > 3 days postnatal age. Maturational factors have a mild impact on sweat chloride concentration.
authors.affiliation: Department of Pediatrics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7145, USA.
authors.forename: Warren
authors.initials: W
authors.lastname: Eng
authors.forename: Vicky A
authors.initials: VA
authors.lastname: LeGrys
authors.forename: Michael S
authors.initials: MS
authors.lastname: Schechter
authors.forename: Matthew M
authors.initials: MM
authors.lastname: Laughon
authors.forename: Pierre M
authors.initials: PM
authors.lastname: Barker
mesh_terms: D001741:Black or African American; D001835:Body Weight; D002712:Chlorides / Q000378:metabolism; D003550:Cystic Fibrosis / Q000175:diagnosis* / Q000378:metabolism*; D005260:Female; D005865:Gestational Age; D006801:Humans; D007223:Infant; D007231:Infant, Newborn / Q000378:metabolism*; D007234:Infant, Premature / Q000378:metabolism*; D008297:Male; D008403:Mass Screening / Q000379:methods*; D015999:Multivariate Analysis; D012189:Retrospective Studies; D012307:Risk Factors; D013048:Specimen Handling / Q000379:methods*; D013542:Sweat / Q000378:metabolism*
chemical_list: D002712:Chlorides