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Quantity not sufficient rates and delays in sweat testing in US infants with cystic fibrosis
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  • Susanna McColley,
  • Alexander Elbert,
  • Runyu Wu,
  • Clement Ren,
  • Marci Sontag,
  • V. Legrys
Susanna McColley
Ann & Robert H.Lurie Children's Hospital of Chicago

Corresponding Author:smccolley@northwestern.edu

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Alexander Elbert
Cystic Fibrosis Foundation
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Runyu Wu
Cystic Fibrosis Foundation
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Clement Ren
Indiana University System
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Marci Sontag
CI International
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V. Legrys
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Background: Diagnostic sweat testing is required for infants with positive newborn screening (NBS) tests for cystic fibrosis (CF). Infants have “quantity not sufficient” (QNS) sweat volumes more often than older children. A comprehensive study of QNS sweat volumes in infants has not previously been reported. Methods: We surveyed US CF Centers to obtain QNS rates in all infants who had sweat testing at < 14 days and < 3 months of age. We then calculated QNS rates reported to the Cystic Fibrosis Foundation Patient Registry (CFFPR) 2010-2018 in 10-day increments from 1 to 60 days of life. We compared QNS sweat tests rates in preterm (< 37 weeks gestational age) versus term infants. We assessed age at sweat test and proportion of infants who did not have a sweat test reported by 60 days of age. Results: Thirty-nine of 144 (27%) of CF Centers reported a mean QNS rate of 10.5 % (range, 0-100) in infants < 14 days old. CFFPR data showed highest QNS rates in the youngest infants and in those born < 37 weeks gestation. The median age at sweat testing decreased over time, but > 22% of infants did not have a sweat test reported by 60 days. Conclusion: Higher QNS rates are seen in the youngest infants with CF, but > 80% of infants < 2 weeks of age have adequate sweat volumes. Sweat testing should not be delayed in infants with a positive CF NBS test.
03 Jun 2020Submitted to Pediatric Pulmonology
04 Jun 2020Submission Checks Completed
04 Jun 2020Assigned to Editor
06 Jun 2020Reviewer(s) Assigned
26 Jul 2020Review(s) Completed, Editorial Evaluation Pending
27 Jul 2020Editorial Decision: Revise Minor
28 Jul 20201st Revision Received
28 Jul 2020Assigned to Editor
28 Jul 2020Submission Checks Completed
28 Jul 2020Reviewer(s) Assigned
06 Aug 2020Review(s) Completed, Editorial Evaluation Pending
06 Aug 2020Editorial Decision: Revise Minor
06 Aug 20202nd Revision Received
07 Aug 2020Submission Checks Completed
07 Aug 2020Assigned to Editor
07 Aug 2020Reviewer(s) Assigned
07 Aug 2020Review(s) Completed, Editorial Evaluation Pending
07 Aug 2020Editorial Decision: Accept
25 Aug 2020Published in Pediatric Pulmonology. 10.1002/ppul.25027