Sweat Chloride Concentration > 60 mmol/L
An abnormally high level of salt in the sweat, directly resulting from malfunctioning CFTR protein channels.
Description
Pilocarpine is applied to the skin and stimulated with a mild electrical current to induce sweating, which is then collected on filter paper. Developed by Gibson and Cooke in 1959, this test exploits the defective ion transport mechanism characteristic of the disease. It remains the gold standard for confirming a clinical diagnosis of cystic fibrosis.