Abstract: The method and system of the invention provide especially for continuously obtaining and analyzing, on a real time basis, sweat from a selected area of skin on the body of a person, especially a neonate, being diagnosed for cystic fibrosis, by causing sweating of the selected area of skin, by placing an electrically positive iontophoretic electrode device of a set of said devices over the selected area of skin preferably within a previously placed receiving and holding device which, following the induction of sweat and removal of the electrically positive iontophoretic electrode device, receives a sweat-sensing electrode device that continuously sends electrical signals to sweat analysis circuitry for providing a digital readout of the ionic composition of the sweat. The receiving and holding device insures recovery and utilization of essentially all of the sweat being produced by the selected area of skin.