<prompt> Which of the following investigation would be diagnostic of cystic fibrosis?Deficiency of the enzyme mucinaseHigh sweat chloride contentAlpha-1 aldolase deficiencyIncreased copper excretion in urine  <response>: A sweat test measures the amount of chloride, a pa of salt, in Sweat. It is used to diagnose cystic fibrosis CF. People with CF have a high level of chloride 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 hard to breathe Ref Davidson 23rd edition pg 944 