A sweat test measures the amount of salt in the sweat of the patient. It is used to diagnose cystic fibrosis (CF). Patients with CF have high levels of salt in their sweat.
CF is a disease that causes mucus build-up in the lungs and other organs. It damages the lungs and makes it difficult to breathe. CF also causes frequent infections and malnutrition. It is an inherited disease, hence it can be passed on from parents to children through the genes.