CT/GC is a medical abbreviation for Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (GC), the bacteria that cause chlamydia and gonorrhea. You’ll most often see this shorthand on lab orders, test results, or clinic paperwork when a healthcare provider screens for both infections at once. Together, chlamydia and gonorrhea are the two most common bacterial sexually transmitted infections in the world, and testing for them is almost always done as a pair because they share similar symptoms, spread the same way, and can infect the same sites in the body.
Why the Two Are Tested Together
Chlamydia and gonorrhea overlap so much in how they behave that screening for one without the other would miss a significant number of infections. Both spread through vaginal, anal, or oral sex. Both can infect the genitals, rectum, and throat. Both are frequently asymptomatic, meaning you can carry and transmit either one without ever feeling sick. And both cause the same serious complications when left untreated, particularly pelvic inflammatory disease and infertility in women.
Because a single test swab or urine sample can detect both bacteria simultaneously, labs process them together. That’s why your paperwork says “CT/GC” rather than listing each infection separately.
How the CT/GC Test Works
The standard test is a nucleic acid amplification test, commonly abbreviated NAAT. It works by detecting tiny amounts of bacterial genetic material in a sample, which makes it far more accurate than older methods like cultures or basic DNA probes. A NAAT can be run on a urine sample, a vaginal swab (which you can often collect yourself), a cervical swab, a rectal swab, or a throat swab, depending on the sites your provider wants to check.
Results typically come back within a few days. A positive CT result means chlamydia was detected. A positive GC result means gonorrhea was detected. It’s possible to test positive for one, both, or neither.
Who Should Get Screened
Routine annual screening is recommended for all sexually active women under 25, and for women 25 and older who have risk factors like a new partner or multiple partners. All pregnant women under 25 should also be screened. Men who have sex with men are advised to test at least once a year at every site of contact (urethra, rectum, throat), and every three to six months if they’re at higher risk. People living with HIV should be screened at their first evaluation and at least annually after that.
Transgender and gender diverse individuals follow screening guidelines based on their anatomy. For example, anyone with a cervix under 25 should be screened annually, regardless of gender identity.
Symptoms to Know About
The reason routine screening matters so much is that both infections are often silent. Most women with gonorrhea have no symptoms at all, and when symptoms do appear, they can easily be mistaken for a bladder or yeast infection. Chlamydia is similarly quiet: symptoms, if they show up, may not appear until several weeks after exposure.
When symptoms do develop, they tend to look like this:
- In women: burning during urination, unusual vaginal discharge, bleeding between periods
- In men: burning during urination, white, yellow, or green discharge from the penis, and occasionally swollen or painful testicles
- Rectal infections: discharge, anal itching, soreness, bleeding, or painful bowel movements
Throat infections from either bacterium rarely cause noticeable symptoms.
What Happens If You Don’t Treat Them
Left untreated, chlamydia and gonorrhea can cause lasting damage. About 10 to 15 percent of women with untreated chlamydia develop pelvic inflammatory disease, an infection of the uterus, fallopian tubes, and surrounding tissue. Chlamydia can also cause “silent” infections in the upper reproductive tract with no symptoms at all, quietly scarring the fallopian tubes. This scarring can lead to chronic pelvic pain, ectopic pregnancy, and infertility. Gonorrhea carries the same risks.
A pregnant woman with either infection can also pass it to her baby during delivery, which can cause eye infections and other complications in the newborn.
Treatment Is Straightforward
Both infections are curable with antibiotics. Chlamydia is treated with a week-long course of oral antibiotics taken twice daily. Gonorrhea is treated with a single antibiotic injection. If you test positive for both, you’ll receive both treatments. Symptoms typically clear within a week or two, though you should avoid sex for seven days after completing treatment to prevent spreading the infection.
Your sexual partners need treatment too, even if they have no symptoms. Some providers use a practice called expedited partner therapy, where they give you a prescription or medication to deliver directly to your partner so they can be treated without a separate office visit. This helps break the cycle of reinfection, which is one of the most common reasons people test positive again shortly after being treated.
How Common These Infections Are
In the United States, provisional 2024 data from the CDC recorded roughly 1.5 million chlamydia cases and about 543,000 gonorrhea cases. Chlamydia is more common in women, while gonorrhea rates are higher in men. Both infections are most prevalent among people in their teens and twenties, which is a major reason screening guidelines focus on younger age groups. Rates for both infections have declined modestly over the past five years, but the numbers remain high enough that routine screening is considered essential for catching the many cases that produce no symptoms.