Breath Aerosol Admittance Orthonormal to Sweat Conductivity as a Reliable 2-D Diagnostic Criterion for Cystic Fibrosis.

Breath aerosol (BA) condensate harvested without cooling from patients with cystic fibrosis (CF) is characterized by drastically reduced admittance (complex conductivity) compared to healthy subjects. The discovered decreased BA ionic strength has clinical confirmation: CF patients suffer from mucus formation, and its clearance from the lungs is carried out with hypertonic saline. The BA admittance orthonormal to the sweat conductivity forms a more reliable 2-D diagnostic criterion as compared to the generally accepted sweat test alone. The 2-D criterion separates healthy subjects from CF patients sector (35.5°) by 13.5°. Importantly, the CF patient with a negative sweat test (special mutation resulting in sweat chloride values close to normal) perfectly matches the CF sector. We strongly believe that a novel diagnostic criterion would allow one to monitor a CF patient condition more precisely upon various therapies.