Endocervical Gram stain is a method to detect bacteria on tissue from the cervix. This is done using a special series of stains.
How the Test is Performed
This test requires a sample of secretions from the lining of the cervical canal (the opening to the uterus).
You lie on your back with your feet in stirrups. The health care provider will insert an instrument called a speculum into the vagina. This instrument is used during regular female pelvic exams. It opens the vagina to better view certain pelvic structures.
After the cervix is cleaned, a dry, sterile swab is inserted through the speculum to the cervical canal and gently turned. It may be left in place for a few seconds to absorb as many germs as possible.
The swab is removed and sent to a laboratory, where it will be smeared on a slide. A series of stains called a Gram stain is applied to the sample. A laboratory technician looks at the stained smear under the microscope for the presence of bacteria. The color, size, and shape of the cells help identify the type of bacteria.
How to Prepare for the Test
Do not douche for 24 hours before the procedure.
How the Test will Feel
You may feel minor discomfort during specimen collection. This procedure feels very much like a routine Pap test.
Why the Test is Performed
This test is used to detect and identify abnormal bacteria in the cervix area. If you develop signs of an infection or think that you have a sexually transmitted disease (such as gonorrhea), this test can help confirm the diagnosis. It can also identify the germ that is causing the infection.
This test is rarely done because it has been replaced with more accurate ones.
A normal result means no abnormal bacteria are seen in the sample.
Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your provider about the meaning of your specific test results.
What Abnormal Results Mean
Abnormal result may indicate:
- Bacterial vaginosis
- Yeast infection
The test may also be performed for gonococcal arthritis, to determine the site of the initial infection.
There is virtually no risk.
If you have gonorrhea or another sexually transmitted disease, it is very important that all of your sexual partners also receive treatment, even if they have no symptoms.
Gram stain of cervix; Gram stain of cervical secretions
Abdallah M, Augenbraun MH, McCormack W. Vulvovaginitis and cervicitis. In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 9th ed. Philadelphia, PA: Elsevier; 2020:chap 108.
Swygard H, Cohen MS. Approach to the patient with a sexually transmitted infection. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 269.
Review Date 10/20/2022
Updated by: Linda J. Vorvick, MD, Clinical Professor, Department of Family Medicine, UW Medicine, School of Medicine, University of Washington, Seattle, WA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.