Ear drainage culture
An ear drainage culture is a laboratory test to check for infection-causing substances in a sample of fluid, pus, wax, or blood from the ear.
See also: Ear drainage
How the test is performed |
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A sample of ear drainage is needed. Your health care provider will use a cotton swab to collect the sample from inside the outer ear canal. In some cases, a sample is collected from the middle ear during ear surgery.
The sample is sent to a laboratory and placed on a special dish (culture media).
The lab team checks the dish every day to see if bacteria, fungi, or viruses have grown. Further tests may be done to specifically identify any substances and determine the best treatment.
How to prepare for the test |
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No preparation is needed for a lab culture.
No pain is associated with using a cotton swab to take a sample of drainage from the outer ear. However, ear pain may be present if the ear is infected.
Ear surgery is performed under general anesthesia, which means you are asleep and feel no pain. See: myringotomy.
Why the test is performed |
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The test may be done if you or your child has:
- An ear infection that is not responding to treatment
- An infection of the outer ear (otitis externa)
- An ear infection with a ruptured eardrum and draining fluid
It may also be done as a routine part of myringotomy.
Note: Ear infections are diagnosed based on symptoms rather than using a culture.
The test is normal if there is no growth on the culture.
Note: Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.
What abnormal results mean |
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Abnormal results may be a sign of infection by bacteria, virus, or fungus.
The test results may reveal which specific organism is causing the infection and help your doctor decide on appropriate treatment.
No risks are involved with swabbing the ear canal. For risks related to ear surgery, see myringotomy.
Ear drainage culture is usually not done because of contamination concerns and difficulty linking a bacteria to the infection. Normal bacteria will likely grow on the ear fluid sent for culture.
Review Date:
3/2/2009
Reviewd By:
Daniel Levy, MD, PhD, Infectious Diseases, Greater Baltimore Medical Center, Baltimore, MD. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.