All 50 states and the District of Columbia are performing newborn screening for cystic fibrosis (CF). Infants who have a positive newborn screen require follow-up with a sweat test. Gibson-Cooke Quantitative Pilocarpine Iontophoresis (GCQPIT) requires collecting sweat in microbore tubing or on gauze/filter paper and analyzing sweat using a chloridometer. This test has many difficulties including specimens that are quantity not sufficient (QNS), many steps of pipetting solutions in the laboratory, and the need for a chloridometer to analyze sweat chloride concentration. The only manufacturer of a chloridometer has ceased production of this instrument. The CF Quantum® Sweat Test System (CFQT) overcomes all of the difficulties of GCQPIT. This pilot study will determine if the CFQT provides results that are equivalent to GCQPIT.