How Gonorrhea Is Diagnosed

Neisseria Gonorrhoeae
BSIP/UIG / Getty Images

If you suspect that you have been infected with gonorrhea, it's important to see a doctor. He or she will collect a urine sample or swab the area that's suspected to be infected (vagina, urethra, or throat, for example) and seek to confirm a diagnosis through use of a bacterial culture, gram staining, or a genetic test. If you're unable to see a physician, or you prefer to handle this privately, there are also kits that allow you to self-test from home.

 Because gonorrhea is often present without symptoms, people at an increased risk of exposure may be advised to seek testing for this and other STDs, regardless of how well they feel.

Labs and Tests

There are three tests used to diagnose gonorrhea, each of which has their benefits and limitations. In addition to gram-staining and bacterial cultures, a newer technology, called the nucleic acid amplification test (NAAT), can provide genetic evidence of infection.

Nucleic Amplification Test (NAAT)

The NAAT is a form of genetic testing first developed in 1993. It is the recommended form of testing for urinary and genital gonorrhea due to its speed and accuracy.

Rather than looking for the bacteria itself, the NAAT identifies the genes unique to N. gonorrhoeae. It does so by obtaining strands of bacterial DNA from either a urine sample or a swab of the vagina, cervix, or urethra (in men). Through a process called thermocycling, the strands are duplicated over and over again until there are roughly a billion copies.

By providing a genetic footprint of infection, the NAAT can deliver highly accurate results within a few hours.  You can expect to receive your tests results within two to three days.

While the Centers for Disease Control and Prevention (CDC) recommends that the NAAT be used to diagnose gonorrheal infections of the rectum and throat, the Food and Drug Administration has not yet approved the test for such use.

Bacterial Culture

A bacterial culture can be highly effective in diagnosing gonorrhea of the genitals, rectum, eyes, or throat. After a taking a swab of the suspected site, the collected cells will be added to a substance designed to promote the growth of N. gonorrhoeae. If there is growth, the test is positive. If there is no growth, the test is negative.

A culture can also be used to determine whether a bacterium is resistant to any of available antibiotic drugs. This is important to learn when a drug fails to clear an infection or there is a disseminated gonococcal infection (DGI), a severe complication in which the bacteria has spread through the bloodstream to multiple organs.

While a culture can provide definitive proof of an infection, the test can be marred if the swab is not taken properly. (A gonorrheal swab require both mucosal cells and infectious discharge.) A bacterial culture is also temperature-sensitive and may be less accurate if there are any mistakes in the handling, storage, incubation, or processing of a sample.

Generally speaking, it can take from five to seven days to receive the results of a bacterial culture.

Gram Staining

Gram staining is a technique in which special dyes are used to stain the walls of a bacteria so that they can be isolated and identified under the microscope.

Gram staining is an effective means of diagnosing a gonorrheal infection in men. It is typically performed by obtaining a swab from the urethra as well as a “first catch” urine sample. (The “first catch” is a method by which urination is withheld for at least an hour before collection and only the first 20 to 30 milliliters of urine are collected from the flow.)

Gram staining, by contrast, is far less accurate for women because the concentration of N. gonorrhoeae is often diffuse and easily mistaken for other naturally occurring bacteria in the vagina. Moreover, because a gram stain has a lower sensitivity, a negative result in asymptomatic men would not be considered definitive.

In both instances, other forms of testing would be necessary.

Typically speaking, you should expect to receive your gram stain test results in two to three days.

Differential Diagnosis

While certain symptoms of gonorrhea may seem to definitive to you (such as a milky discharge from the penis), there may be other causes that a doctor will want to explore that have strikingly similar features. These include:

  • Urinary tract infections
  • Herpes simplex urethritis
  • Vaginitis
  • Bacterial vaginosis
  • Internal hemorrhoids
  • Epididymitis
  • Mucopurulent cervicitis
  • Bacterial conjunctivitis
  • Orchitis

Self-Checks/At-Home Testing

If you think you may have been exposed to gonorrhea, you might look for signs and symptoms before seeking out a test. Remember, though, they don't occur often and, if they do, can easily be mistaken for another concern. It's wise to be tested to confirm a diagnosis or put your mind at ease—officially.

Stigma, embarrassment, and fear of disclosure are just some of the reasons why some people avoid getting tested for STDs. In fact, according to a report from the CDC, undiagnosed STDs cause infertility in more than 20,000 American women each year.

To this end, an increasing number of public health advocates have endorsed the use of at-home STD tests, which provide consumers the autonomy and confidentiality they desire.

The most popularly marketed home kits for gonorrhea require you to collect the swab and/or urine samples at home and mail them to the lab for analysis. You then log onto a secure website to get your results in three to five business days.

Despite the appeal of at-home testing, there are many drawbacks. Collecting samples tends to be more difficult than manufacturers suggest, and user error is rife. Most companies are neither clear on the type of tests they provide nor their accuracy (as measured by sensitivity/specificity). Moreover, the cost of the kits can be prohibitive, starting at $90 for a single STD and over $300 for a comprehensive STD screen.

One test to actively avoid is the rapid gonorrhea test strip. While the urine- and fluid-based tests can deliver results in as little as 15 minutes, they offer a sensitivity of only 60 percent to 70 percent—meaning that as many as two of every five tests will return a false-negative result.

If You Test Positive

If a positive result for gonorrhea is received, a comprehensive STD screening should be performed, including for chlamydia, syphilis, trichomoniasis, and HIV. Co-infection is common among these STDs, and some, like HIV, are better able to establish infection if another is present. If you used an at-home test, seeking this additional screening from a physician is advised.

It is highly suggested that current and recent sex partners be contacted and encouraged to get tested (and treated, if needed). While the CDC recommends that you or your provider notify all partners you had sex with in the 60 days prior to the onset of symptoms or the confirmation of your diagnosis, you may want to go further back than that.

Once treatment is completed, a follow-up test is not required to confirm the infection has cleared as long as the recommended antibiotics are used. However, given the high rates of reinfection, your doctor may request that you be retested in three months irrespective of whether your partners have been treated or not.

Screening Recommendations

Gonorrhea is the second most common STD in the United States, accounting for over 800,000 infections each year. To this end, the U.S. Preventive Services Task Force recommends that screening for gonorrhea and other common STDs be performed in people at increased risk of exposure and/or disease complications.

Among the recommendations:

  • Gonorrhea and chlamydia should be screened in all sexually active women who are at increased risk of exposure.
  • Gonorrhea and chlamydia should be screened in pregnant women who are at increased risk.
  • Syphilis, hepatitis B, and HIV should be screened in all pregnant women.
  • Syphilis, hepatitis B, and HIV should be screened in men or women who are at increased risk.
  • HIV testing should be conducted as part of a routine doctor's visit for all people ages 15 to 65.

You are considered to be at risk if you've ever had multiple sex partners or have engaged in unprotected sex (including oral sex). This is true even if the potential exposure happened years ago. If you are infected, you will continue to be contagious until you've been treated and risk bringing the infection into a new relationship without even knowing. Remember, too, that your partner's sexual history and behaviors can affect your risk of STDs as well.

See your doctor for screening. Or, to find a testing site near you, visit the CDC's online locator. Many of the listed clinics offer low-cost or no-cost confidential testing for qualified residents.

Sources:

Centers for Disease Control and Prevention (CDC). 2015 Sexually Transmitted Diseases Treatment Guidelines: Gonococcal Infections. Atlanta, Georgia; issued June 4, 2015; updated January 4, 2018.

CDC. CDC Fact Sheet: Reported STDs in the United States, 2016 - High Burden of STDs Threaten Millions of Americans. Issued September 2017.

CDC. Gonorrhea - CDC Fact Sheet (Detailed Version). Issued October 25, 2016; updated September 26, 2017.

Lee, K.; Ngo-Metzger, Q.; Wolff, T. et al. Sexually Transmitted Infections: Recommendations from the U.S. Preventive Services Task Force. Am Fam Physician. 2016; 94(11):907-915.

Workowski, K.; Bolan, G.; Centers for Disease Control and Prevention. Sexually transmitted diseases treatment guidelines, 2015.& MMWR Recomm Rep. 2015; 2015; 64(33):924.