A sweat chloride level greater than which value is considered diagnostic for cystic fibrosis in the appropriate clinical context?

Prepare for the Registered Respiratory Therapist CSE with comprehensive flashcards and multiple-choice questions, including hints and explanations. Ace your exam with confidence!

Multiple Choice

A sweat chloride level greater than which value is considered diagnostic for cystic fibrosis in the appropriate clinical context?

Sweat chloride testing is the primary diagnostic tool for cystic fibrosis when done correctly because CFTR dysfunction causes salt to be poorly reabsorbed in the sweat duct, leading to elevated chloride in sweat. A value above 60 mEq/L is diagnostic for CF in the appropriate clinical context, as this level has high specificity for the disease. The test is usually performed using pilocarpine iontophoresis to collect sweat accurately. Values in the intermediate range (roughly 30–59 mEq/L) are not diagnostic on their own and often require repeat testing or genetic confirmation. Newborn screening can identify risk but is not diagnostic by itself, and chest X-ray does not diagnose CF.

Sweat chloride testing is the primary diagnostic tool for cystic fibrosis when done correctly because CFTR dysfunction causes salt to be poorly reabsorbed in the sweat duct, leading to elevated chloride in sweat. A value above 60 mEq/L is diagnostic for CF in the appropriate clinical context, as this level has high specificity for the disease. The test is usually performed using pilocarpine iontophoresis to collect sweat accurately. Values in the intermediate range (roughly 30–59 mEq/L) are not diagnostic on their own and often require repeat testing or genetic confirmation. Newborn screening can identify risk but is not diagnostic by itself, and chest X-ray does not diagnose CF.

More practice questions