Facemasks are just as good as mouthpieces and noseclips for breathing test measurements in preschool-age children, a study found.

Multiple breath washout (MBW), a test that uses this equipment, measures lung function, making it possible to detect early lung disease. The study, “Comparison of facemask- and mouthpiece-interfaces for multiple breath washout measurements,” was published in the Journal of Cystic Fibrosis.

There is interest among doctors and researchers in using MBW to track lung function in patients with cystic fibrosis, starting as early as possible in life. The test involves placing a facemask or mouthpiece and nose clip on the patient’s face, and using a marker gas, such as helium, to calculate the volume of the breaths of air it takes to empty the lungs of the inhaled gas.