An endocervical gram stain (EGS) is a diagnostic test that is used to check for abnormal bacteria around the cervix.
For this test, a small sample of tissue is taken from the cervical canal (the opening of the uterus) and then sent to a laboratory. At the laboratory, a specialist applies a number of different stains (gram stain) to the sample, which helps him or her to better view any bacteria that are present. The specialist will check the shape, size, and color of the bacteria to determine if it is abnormal.
EGS is commonly used to check for sexually transmitted infections (STIs), such as gonorrhea and chlamydia. It may also be used to check for gonococcal arthritis, a complication of gonorrhea that causes joint inflammation (swelling).
EGS may also be called a gram stain of cervix.
An EGS is done to check for abnormal bacteria around the cervix. Your health care provider may also administer this test if he or she suspects you have an STI. An EGS can detect STIs such as:
- gonorrhea: a common STI with symptoms such as painful urination and abnormal discharge
- bacterial vaginosis: an STI characterized by a fish-like odor and grayish discharge
- chlamydia: the most commonly diagnosed STI; chlamydia does not always show symptoms, but may cause painful intercourse and urination
- yeast infection: characterized by vaginal itchiness and a thick discharge
- gonococcal arthritis: inflammation of a joint caused by a gonorrhea infection
An EGS is very similar to a pap smear, which is also done using a swab and a speculum. You may find the test to be a little uncomfortable or awkward. However, you should not feel any pain.
You should not douche (clean your vaginal area with special washes) for 24 hours before the EGS. Douching may mask the bacteria in the cervix.
An EGS will generally consist of a few basic steps:
- You will change into a gown and lie down on a table with your feet in stirrups at the end of the table.
- Your doctor will use a metal or plastic instrument called a speculum to gently stretch your vagina open. This will allow him or her to get a better view of the organs in your cervix.
- Your doctor will clean your cervix so there is no discharge.
- He or she will then place a sterile, dry cotton swab against the cervical canal. He or she may also rotate the swab and leave it in for a few seconds to allow bacteria to settle on it.
- Your doctor will then tell you the procedure is done and that you may get dressed.
- Your doctor will send the swab to a laboratory, where it will be rubbed against a slide and stained with a gram stain. The laboratory technician will then study the stain under a microscope to look for any abnormal bacteria.
Your healthcare provider will contact you with any abnormal test results. Some doctors do not call when test results are normal. You may want to ask your doctor about his or her notification procedures.
There are no risks associated with an EGS. However, an EGS may cause a little bit of bleeding if your cervix is inflamed.
An EGS is a simple test. There are no complications associated with it. However, complications may occur if STIs are left untreated.
A normal test result means that no abnormal bacteria were detected on your EGS. Normal test result ranges may vary depending on the laboratory.
If you receive an abnormal test result, follow the guidance of your doctor. He or she may ask you to come back in for a follow-up examination or further testing.
Many STIs can be treated with antibiotics.
If you do have an STI, you should contact any sexual partners and encourage them to seek testing and treatment. They may have no symptoms and unknowingly spread the STI.
Ask your health care provider if you have any questions about your EGS results.