Middle ear infections are usually diagnosed using a health history, a physical exam, and an ear exam.

With a middle ear infection, the eardrum, when seen through a pneumatic otoscope, is red or yellow and bulging. In the case of fluid buildup without infection (otitis media with effusion), the eardrum can look like it's bulging or sucking in. In both cases, the eardrum doesn't move freely when the pneumatic otoscope pushes air into the ear.

Other tests can include:

• Tympanometry, which tests the movement of the eardrum. The tip of a hand-held tool is placed just inside the ear. It changes the air pressure inside the ear. Then, the tool measures how the eardrum responds.
• Hearing tests. A hearing test is recommended for children who have had fluid in one or both ears (otitis media with effusion) for a total of 3 months. Hearing tests may be done sooner if hearing loss is suspected.
• Tympanocentesis. When fluid stays behind the eardrum (chronic otitis media with effusion) or infection continues even with antibiotics, tympanocentesis can remove the fluid. The doctor uses a needle to pierce the eardrum and suck out the fluid. A sample is usually tested for culture and sensitivity. These tests reveal what kind of bacteria is causing the infection and which medicine is best for treatment.
• Blood tests, which are done if there are signs of immune problems.