B. Tympanometry: tympanometry can be used to confirm the diagnosis of OME

This option is based on cohort studies and a balance of benefit and harm.

Diagnosing OME correctly is fundamental to proper management. Moreover, OME must be differentiated from AOM to avoid unnecessary antimicrobial use.

OME is defined as fluid in the middle ear without signs or symptoms of acute ear infection. The tympanic membrane is often cloudy with distinctly impaired mobility, and an air-fluid level or bubble may be visible in the middle ear. Conversely, diagnosing AOM requires a history of acute onset of signs and symptoms, the presence of middle-ear effusion, and signs and symptoms of middle-ear inflammation. The critical distinguishing feature is that only AOM has acute signs and symptoms. Distinct redness of the tympanic membrane should not be a criterion for prescribing antibiotics, because it has poor predictive value for AOM and is present in ~5% of ears with OME.

The AHRQ evidence report systematically reviewed the sensitivity, specificity, and predictive values of 9 diagnostic methods for OME. Pneumatic otoscopy had the best balance of sensitivity and specificity, consistent with the 1994 guideline. Meta-analysis revealed a pooled sensitivity of 94% (95% confidence interval: 91%–96%) and specificity of 80% (95% confidence interval: 75%–86%) for validated observers using pneumatic otoscopy versus myringotomy as the gold standard. Pneumatic otoscopy therefore should remain the primary method of OME diagnosis, because the instrument is readily available in practice settings, cost-effective, and accurate in experienced hands. Non–pneumatic otoscopy is not advised for primary diagnosis.

The accuracy of pneumatic otoscopy in routine clinical practice may be less than that shown in published results, because clinicians have varying training and experience. When the diagnosis of OME is uncertain, tympanometry or acoustic reflectometry should be considered as an adjunct to pneumatic otoscopy. Tympanometry with a standard 226-Hz probe tone is reliable for infants 4 months old or older and has good interobserver agreement of curve patterns in routine clinical practice. Younger infants require specialized equipment with a higher probe tone frequency. Tympanometry generates costs related to instrument purchase, annual calibration, and test administration. Acoustic reflectometry with spectral gradient analysis is a low-cost alternative to tympanometry that does not require an air-tight seal in the ear canal; however, validation studies primarily have used children 2 years old or older with a high prevalence of OME.

Although no research studies have examined whether pneumatic otoscopy causes discomfort, expert consensus suggests that the procedure does not have to be painful, especially when symptoms of acute infection (AOM) are absent. A nontraumatic examination is facilitated by using a gentle touch, restraining the child properly when necessary, and inserting the speculum only into the outer one third (cartilaginous portion) of the ear canal. The pneumatic bulb should be compressed slightly before insertion, because OME often is associated with a negative middle-ear pressure, which can be assessed more accurately by releasing the already compressed bulb. The otoscope must be fully charged, the bulb (halogen or xenon) bright and luminescent, and the insufflator bulb attached tightly to the head to avoid the loss of an air seal. The window must also be sealed.