Health Guide

Bacterial culture, conjunctiva

What is this test?

This test detects and identifies bacteria from a culture of fluid or discharge from an eye. This test is used to help diagnose a possible bacterial cause of conjunctivitis or "pink eye". This test is also used when the "pink eye" does not improve after initial antibiotic treatment[1][2][3][4].

Why do I need this test?

Laboratory tests may be done for many reasons. Tests are performed for routine health screenings or if a disease or toxicity is suspected. Lab tests may be used to determine if a medical condition is improving or worsening. Lab tests may also be used to measure the success or failure of a medication or treatment plan. Lab tests may be ordered for professional or legal reasons. You may need this test if you have:

  • Bacterial pinkeye

When and how often should I have this test?

When and how often laboratory tests are done may depend on many factors. The timing of laboratory tests may rely on the results or completion of other tests, procedures, or treatments. Lab tests may be performed immediately in an emergency, or tests may be delayed as a condition is treated or monitored. A test may be suggested or become necessary when certain signs or symptoms appear.

Due to changes in the way your body naturally functions through the course of a day, lab tests may need to be performed at a certain time of day. If you have prepared for a test by changing your food or fluid intake, lab tests may be timed in accordance with those changes. Timing of tests may be based on increased and decreased levels of medications, drugs or other substances in the body.

The age or gender of the person being tested may affect when and how often a lab test is required. Chronic or progressive conditions may need ongoing monitoring through the use of lab tests. Conditions that worsen and improve may also need frequent monitoring. Certain tests may be repeated to obtain a series of results, or tests may need to be repeated to confirm or disprove results. Timing and frequency of lab tests may vary if they are performed for professional or legal reasons.

How should I get ready for the test?

Ask the healthcare worker for information about how to prepare for this test.

How is the test done?

The most common way this test is done is with a sterile moistened swab. The swab will be wiped over the surface of your eye or the inside of your eyelid. The swab will collect any pus or drainage[5][6].

How will the test feel?

The amount of discomfort you feel will depend on many factors, including your sensitivity to pain. Communicate how you are feeling with the person doing the test. Inform the person doing the test if you feel that you cannot continue with the test.

During an eye culture, you may feel mild eyelid discomfort when the sample is collected. No anesthetic (numbing or pain medicine) is used for this test. Ask the healthcare worker what to expect during this test.[5].

What should I do after the test?

Ask the healthcare worker to instruct you on what to expect after this test is completed. If you have questions or concerns about what to expect after the test is completed, talk to the healthcare worker.

What are the risks?

Ask the healthcare worker to explain the risks of this test or procedure to you before it is performed.

What are normal results for this test?

Laboratory test results may vary depending on your age, gender, health history, the method used for the test, and many other factors. If your results are different from the results suggested below, this may not mean that you have a disease. Contact your healthcare worker if you have any questions. The following is considered to be a normal result for this test:

  • Adults and Children: Negative or no growth

What follow up should I do after this test?

Ask your healthcare worker how you will be informed of the test results. You may be asked to call for results, schedule an appointment to discuss results, or notified of results by mail. Follow up care varies depending on many factors related to your test. Sometimes there is no follow up after you have been notified of test results. At other times follow up may be suggested or necessary. Some examples of follow up care include changes to medication or treatment plans, referral to a specialist, more or less frequent monitoring, and additional tests or procedures. Talk with your healthcare worker about any concerns or questions you have regarding follow up care or instructions.

Where can I get more information?

Related Companies

  • American Academy of Ophthalmology -


[1] Nicoll D, McPhee SJ, Pignone M, et al (Eds): Pocket Guide to Diagnostic Tests, 3rd. McGraw-Hill, New York, NY, United States, 2001.

[2] Leibowitz HM: The red eye. N Engl J Med 2000; 343(5):345-351.

[3] Morrow GL & Abbott RL: Conjunctivitis.. Am Fam Physician 1998; 57(4):735-746.

[4] Gigliotti F, Williams WT, Hayden FG, et al: Etiology of acute conjunctivitis in children.. J Pediatr 1981; 98:531-536.

[5] Cantor RM: Ocular and paranasal sinus infections in infancy and childhood.. Top Emerg Med 1990; 12:75-87.

[6] Fischbach FFischbach F: A Manual of Laboratory Diagnostic Tests, 2nd. J.B. Lippincott Company, Philadelphia, PA, 1984.

Last Updated: 7/4/2018
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