Your doctor would like to have this test done to help them decide what is wrong with your child. Mainly it is to exclude a condition called Primary Cilia Dyskinesia.
This is a rare condition, which effects the cilia movement and causes increased chest infections. The doctor would like to see how fast your child’s cilia beat. If your child is found to have this condition your consultant will discuss with you the implications. This is the only defining test that can be done for this condition.
There is no preparation needed on your part before the procedure.