Sweat testing infants detected by cystic fibrosis newborn screening

J Pediatr. 2005 Sep;147(3 Suppl):S69-72. doi: 10.1016/j.jpeds.2005.08.015.


Objective: Describe and define limitations of early pilocarpine iontophoresis (sweat testing) for cystic fibrosis (CF) newborn screening (NBS).

Study design: Population-based results from follow-up of CF NBS-positive newborns.

Results: Insufficient quantity of sweat is more likely if the sweat test is done too early, but testing is generally successful after 2 weeks of age. Sweat chloride levels drop over the first weeks of life. CF carriers have higher sweat chloride concentrations than non-carriers.

Conclusions: Sweat testing can be performed effectively after 2 weeks of age for CF NBS-positive newborns. Earlier testing has a higher risk of insufficient sweat for completing testing.

Publication types

  • Research Support, Non-U.S. Gov't
  • Validation Study

MeSH terms

  • Age Factors
  • Algorithms
  • Chlorides / analysis*
  • Cystic Fibrosis / diagnosis*
  • Cystic Fibrosis / genetics
  • DNA Mutational Analysis
  • Decision Trees
  • Early Diagnosis
  • False Negative Reactions
  • False Positive Reactions
  • Follow-Up Studies
  • Humans
  • Infant, Newborn
  • Iontophoresis / methods*
  • Iontophoresis / standards
  • Linear Models
  • Massachusetts
  • Muscarinic Agonists
  • Neonatal Screening / methods*
  • Neonatal Screening / standards
  • Patient Selection
  • Pilocarpine
  • Reference Values
  • Referral and Consultation
  • Risk Factors
  • Sweat / chemistry*


  • Chlorides
  • Muscarinic Agonists
  • Pilocarpine