Micro- ̄owcell conductometric sweat analysis for cystic ®brosis diagnosis

This paper describes a device speci®cally designed to facilitate neonatal sweat testing. The components are sized appropriately for attachment to the limbs of newborns. Iontophoretic electrodes, with pilocarpine gel inserts, are latched into small holders attached by straps to the limb. The holder at the anodic site remains in place to receive and align the sensor cell, which uses a conical collecting surface to channel the sweat directly and anaerobically from the sweat ducts to the continuous ̄ow-through conductivity cell within its body. A crib-side analysis unit incorporates an iontophoretic power supply and displays a continuous readout of sweat electrical conductivity. The average conductivity during a speci®c time interval and the initial sweating rate are automatically displayed. The method, which simpli®es sweat tests, is currently being assessed in three neonatal clinical trials to test its ability to reduce test failures in the newborn due to insuf®cient sweat.