Ear drainage culture

How the Test is Performed:
A sample of ear drainage is placed on culture media in containers for the purpose of growing microorganisms (bacteria, fungus, or viruses) in the laboratory, which will later be identified under the microscope. The microbiologist inspects the cultures daily for growth. If microorganisms are detected, other tests may be initiated to determine the sensitivity of the organism to medications ( sensitivity analysis ). Antibiotic therapy can then be determined based on these results.

How to Prepare:
There is no preparation.

How it Feels:
The specimen will be collected from a cotton swab placed gently inside the ear canal. No pain is associated with the test; however, ear pain may be present already if infection is suspected. If a myringotomy (surgical opening of the eardrum) is performed for relief of a painful, bulging tympanic membrane in otitis media , fluid will be collected at this time. Rarely, a needle may be inserted through the tympanic membrane (eardrum) to obtain a sample of the fluid.

Risks:
No risks are involved with swabbing the ear canal. Risks of myringotomy and needle aspiration include bleeding , infection, and hearing loss .

Why this Test is Performed:
The test may be performed for an infection of the outer ear (see otitis externa; acute ), as a routine part of myringotomy , otitis media with ruptured eardrum and draining fluid, and otitis media not responding to treatment. Most ear infections are diagnosed by clinical symptoms rather than by obtaining a culture.

Normal Values:
No organisms seen on the culture is normal.

Abnormal Results:
Abnormal results indicate infection. The infection may be bacterial, viral, or fungal. The causative organism and an effective medication to treat the organism, if available, are indicated in the results.

Cost:
The estimated cost is $35.

Special Considerations:
Not applicable.


This is an illustration of the external, middle, and inner ear. The detailed section is of the eardrum and the three tiny bones that conduct sound from the drum to the cochlea.



This is an illustration of the outside of the ear showing normal landmarks and several abnormal features including: earlobe creases, a preauricular pit, and a preauricular tag.