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Ear drainage culture

An ear drainage culture is a lab test to check for infection-causing substances in a sample of fluid, pus, wax, or blood from the ear.

How the Test is Performed

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 lab 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. More tests may be done to look for specific substances and determine the best treatment.

How to Prepare for the Test

You do not need to prepare for this test.

How the Test will Feel

Using a cotton swab to take a sample of drainage from the outer ear is not painful. However, ear pain may be present if the ear is infected.

Ear surgery is done using general anesthesia. You will be asleep and feel no pain.

Why the Test is Performed

The test may be done if you or your child has:

  • An ear infection that is not getting better with 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.

Normal Results

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

Abnormal results may be a sign of infection by bacteria, virus, or fungus.

The test results may show which organism is causing the infection. It will help your doctor decide on the right treatment.

Risks

No risks are involved with swabbing the ear canal. Ear surgery may involve some risks.

Alternative Names

Culture - ear drainage

References

Buttaravoli P, Leffler SM. Otditis extgerna (swimmer's ear), acute. In: Buttaravoli P, Leffler SM, eds. Minor Emergencies. 3rd ed. Philadelphia, PA: Mosby Elsevier; 2012:chap 34.

Murray, PR. The clinician and the microbiology laboratory. In: Bennett E, Dolin R, Blaser MJ, eds. Mandell, Douglass, and Bennett's Principles and Practice of Infectious Diseases. 8th ed. Philadelphia, PA: Elsevier Churchill Livingstone; 2014:chap 16.

Update Date: 8/30/2014

Updated by: Neil K. Kaneshiro, MD, MHA, Clinical Assistant Professor of Pediatrics, University of Washington School of Medicine, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.

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