How does acoustic reflectometry diagnose viral ear infections?

Acoustic reflectometry is a test used to measure fluid buildup in cases of viral ear infection. Unlike tympanometry, which tests movement of the eardrum with air pressure, acoustic reflectometry uses sounds to test the volume of fluid in the middle ear. It is not, however, a hearing test. Your doctor may recommend a hearing test in addition to acoustic reflectometry to see if your hearing has been damaged by the ear infection.