The nasal potential difference test (nasal PD test) measures how well
salts (sodium and chloride) flow across the mucous membranes in the nose. This
type of test can be helpful when the results of a sweat test or a genetic test
are not clear.
In this test, electrodes are placed inside the nose and liquids are
run through the nose. There is also a needle placed in the forearm that
connects to a machine. Because this test can be uncomfortable, your child may
need medicine to help him or her relax before having the test.
This test is not used very often because it can be
difficult to do and because it is not available in many places.
How this information was developed to help you make better health decisions.