How STIs Are Diagnosed

Diagnosing and treating a sexually transmitted infection (STI) in the early stages is important to avoid complications and prevent transmission of the infection. Most STIs, such as chlamydia, gonorrhea, human immunodeficiency virus (HIV), and human papillomavirus (HPV), are diagnosed with a blood, urine, or swab test performed in a healthcare provider's office or sexual health clinic.

STIs cause a diverse variety of symptoms or may present with no symptoms at all. If you think you may have been exposed to an STI it is important to get tested.

According to the Centers for Disease Control and Prevention (CDC), there were 26 million new cases of STIs diagnosed in the United States in 2018. Left untreated, STIs can lead to serious issues such as infertility, pelvic inflammatory disease, and birth defects.

How Are Different STDs Diagnosed? - Illustration by Nusha Ashjaee

Verywell / Nusha Ashjaee

Self-Checks/At-Home Testing

You may recognize what you believe to be symptoms or signs of an STI, such as discharge or pain. Many of these symptoms can be mistaken for another health condition such as a urinary tract or yeast infection.

So, while symptoms of an STI should prompt you to see a healthcare provider, they alone are not enough for you to confirm that you have an STI. Likewise, a lack of symptoms isn't enough to confirm that you don't.

At-home testing is available for many STIs, including chlamydia, gonorrhea, syphilis, hepatitis B, herpes simplex virus-2, HIV, and HPV. You collect urine, blood, and/or vaginal, rectal, or oral swabs and mail the sample(s) to a laboratory. Results are usually available in two to 10 days and are typically viewable online. There are also HIV oral tests that can give results at home within minutes.

Self-tests cost between $50 and $300, depending on the number of STIs they screen for. The kits can be ordered online and may be available at your local pharmacy.

Many people prefer the privacy of at-home STI testing. However, research shows that results are not as accurate as those of tests performed by a healthcare professional, likely due to user-error when collecting samples. 

If selecting an at-home STI test, look for products that have been approved by the U.S. Food and Drug Administration (FDA) and certified by the Clinical Laboratory Improvement Amendments (CLIA).

If you test positive for an STI using a self-test, it is important to see a healthcare provider for confirmatory testing.

Labs and Tests 

STI screening is not an automatic part of a routine physical or annual gynecologic exam as standard health care. Be proactive about your sexual health and ask your healthcare provider to test you for STIs.

There is no standard STI panel, so talk honestly with your healthcare provider about your risk factors and be clear about STIs you may have been exposed to. All STIs that affect both men and women can be screened for in both sexes with the exception of human papillomavirus (HPV), which can only be screened for in women.

Your healthcare provider will take a detailed sexual-health history and perform a physical examination before deciding on what tests to order and collecting samples for the lab. These may include:

  • Urine
  • Blood
  • Swab samples from the penis, vagina, urethra, cervix, anus, cheek, throat, or open sores

Don't assume that you've been tested for something unless your healthcare provider explicitly states it. And don’t hesitate to ask for additional tests if you think they are appropriate.

Bacterial & Fungal STIs

Bacterial/Fungal STI Blood Test Urine Test Swab Test
Bacterial vaginosis No No Yes
Chlamydia No Yes Yes
Gonorrhea No Yes Yes
Syphilis Yes No Yes
Trichomoniasis No Yes Yes

Gonorrhea and Chlamydia Testing

Gonorrhea and chlamydia are the easiest STIs to test for. Young women are sometimes screened for these automatically. Anyone with a new partner or multiple partners should probably be screened for these STIs as well.

A nucleic acid amplification test (NAAT) is commonly performed to check for genetic evidence of infection using urine or swab samples and can provide results within a few business days. Swab tests that are processed using culture techniques, may take up to a week.

Syphilis Testing

Syphilis testing is typically performed with a blood test and is recommended for pregnant women and certain high-risk groups such as patients with another STI, men who have high-risk sex with men, and prison inmates. In the absence of symptoms, however, other people are not usually tested for syphilis due to a risk of false positives.

If you are tested using a VDRL test (blood test), you should get your results in under a week. There is also a rapid test, which can provide results in less than 15 minutes, but it is not available at all healthcare provider's offices.

Trichomoniasis and Bacterial Vaginosis Testing

For women, rapid tests are available for trichomoniasis and bacterial vaginosis (BV). (Though not classified as an STI, a woman's risk of BV increases with the number of sexual partners she has had.) These tests are performed in the healthcare provider's office and done using a vaginal swab. Results can be available in as little as 10 minutes and conveyed to you before you leave. Swabs can also be sent to a laboratory for testing; your practitioner can share results when they're returned.

Trichomoniasis can also be detected in a urine sample that is sent to a lab for testing. The results can take a day to a week to be available. Men are unlikely to be screened for trichomoniasis unless their partner is positive, but a urine test can be requested.

Viral STIs

Viral STI Blood Test Urine Test Swab Test
Hepatitis B Yes No No
Herpes Yes No Yes
HIV Yes Yes Yes
HPV No No Yes

Hepatitis B Testing

Hepatitis B is diagnosed with a series of blood tests. Test results usually take a day or more, depending on where the sample needs to be sent.

There is a rapid test that gives results in 20 minutes, but it must be confirmed with an additional blood test. 

Herpes Testing

Herpes can be diagnosed with a blood test or by taking a swab test from a sore if symptoms are present. Due to the possibility of false positives, the CDC does not recommend testing for herpes in the absence of symptoms, unless you have knowingly been exposed to herpes. You can, however, request herpes testing if you have had multiple sexual partners and want to be screened for all STIs.

Due to the performance limitations of a blood test, it is recommended that a second test be done using another method to confirm the results.

Depending on the lab, results can come back as quickly as one day for blood tests and three days for cultures. It's important to note that a herpes blood test can only confirm the infection is present, but cannot differentiate between oral and genital herpes. 

HIV Testing

HIV tests are usually performed on blood or oral fluid, but some clinics can test using a urine sample. Everyone should be tested, at least once, for HIV. People who engage in risky behavior should be tested more often.

Rapid HIV tests can give results in as little as 30 minutes. More often, a blood or saliva sample will be sent out and you'll get your results in under a week.

Timing Matters

Standard herpes and HIV tests look for antibodies in the blood, but they are not detectable immediately after contracting the virus. HIV tests are also routinely done with an oral swab test.

It takes at least two weeks and as much as three months post-exposure for herpes to render a positive test result. Antibodies to HIV are detectable in the blood two to six weeks after exposure, though it can take up to three months.

If you are being screened after a risky encounter, it is important to let your healthcare provider know. They may be able to do a nucleic acid test (NAT) on a blood sample. This test can detect the HIV virus itself, usually 10 to 33 days after an exposure.

If you test negative for HIV after exposure, it is a good idea to get retested after three months to be sure.

HPV Testing

HPV is easier to detect in women than men because the only FDA-approved test for diagnosing HPV uses cervical cells. Testing can be done during a pelvic exam—either by itself or at the same time as a Pap smear. Results typically take one to three weeks.

While other viral STIs can be diagnosed through blood work, the viral load of HPV changes over time as the body fights the virus. This makes HPV blood tests unreliable and not recommended by the FDA.

How to Ask for an STI Test

Asking for STI testing can feel awkward, but it is an important part of your sexual health. Since there is no such thing as a standard comprehensive STI screening, tell your healthcare provider the specific STI(s) you think you've been exposed to so they can be tested for.

If you aren't sure about what tests you need, be honest with your healthcare provider about your risk of exposure and concerns.

If helpful, here are a few ways to consider stating your request:

  • "Although I always practice safer sex, I like to be screened on a yearly basis for my own peace of mind. Therefore, I would like to be tested for chlamydia, gonorrhea, syphilis, herpes, hepatitis, HIV, and trichomoniasis."
  • "I'm about to start having sex with a new partner and we'd both like to be tested beforehand. Could you test me for the bacterial STIs, HIV, HPV, hepatitis, and herpes?"
  • "I recently had unprotected sex and I'm worried that my partner may have exposed me to something. Could you give me a full battery of STI tests including chlamydia, gonorrhea, syphilis, HIV, herpes, and hepatitis? I know it might take some of those tests a bit of time to turn positive, but it would make me feel better to do something."

Access, Coverage, and Privacy

STI testing is often, but not always, covered by insurance. If your insurance does not cover it, testing is usually available at a low-cost or free STI clinic.

Most healthcare providers are willing to screen you for STIs if you ask, but some practitioners may decide not to test you. If this happens, you can find another medical professional or visit a Planned Parenthood or STI clinic. 

STI test results are covered by the Health Insurance Privacy and Portability Act (HIPPA). That means that access to your results is limited to you, your healthcare provider, and anyone you choose to share them with.

Chlamydia, gonorrhea, syphilis, HIV, and hepatitis are nationally notifiable diseases, which means cases are reported to the CDC for surveillance tracking. The database tracks the number of cases of many communicable diseases including measles, Lyme disease, and food poisoning, but it does not track personal information such as your name. 

If you are diagnosed with a notifiable STI, your healthcare provider will report it to the local state health department, which may contact you for a list of sexual partners for contact tracing purposes. Due to healthcare privacy laws, your STI status cannot be disclosed by anyone other than yourself.

Differential Diagnoses

What appears to be an STI symptom can be caused by a different condition. For example, genital itching can be caused by a yeast infection, menopause, irritants or allergens, scabies, or pubic lice. A lump or sore in the genital region can be due to an infected hair follicle or a Bartholin gland cyst (in women).

If you have these or other symptoms of an STI and have had unprotected sex or engaged in other high-risk behaviors, talk to your healthcare provider about getting tested for STIs.

A negative test can give you peace of mind and get you closer to getting a proper diagnosis, and a positive test will help you get treatment and prevent spreading the infection to your partner.

A Word From Verywell

If you are open and upfront about your reasons for wanting to test, most healthcare providers will respect you and your desire to take care of your health. However, if you get any other reaction from your practitioner, it is OK to look elsewhere for medical care. Your sexual decisions are your own. Your healthcare provider's job is to take care of your health and help you to do the same.

Frequently Asked Questions

  • What STIs can be detected by a urine test?

    Chlamydia, gonorrhea, trichomoniasis, and HIV can be diagnosed using a urine test. 

  • What STIs can be detected by blood tests?

    Syphilis, hepatitis, herpes, and HIV are diagnosed using a blood test. 

  • What STIs are detected by swab test?

    Bacterial vaginosis, chlamydia, gonorrhea, trichomoniasis, herpes, HIV, HPV, and syphilis can be diagnosed using a swab test. 

  • How long does it take for an STI to show up in tests?

    It depends. Some STIs, like chlamydia, gonorrhea, and syphilis, can be detectable in a matter of days to a few weeks. Others, like HIV, can take three months to show up as positive on a blood test. 

12 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  5. Seña AC, Miller WC, Hobbs MM, et al. Trichomonas vaginalis infection in male sexual partners: implications for diagnosis, treatment, and prevention. Clin Infect Dis. 2007;44(1):13-22. doi:10.1086/511144

  6. Centers for Disease Control and Prevention. Genital herpes screening: FAQ.

  7. Legoff J, Péré H, Bélec L. Diagnosis of genital herpes simplex virus infection in the clinical laboratoryVirol J. 2014;11:83. doi:10.1186/1743-422X-11-83.

  8. Centers for Disease Control and Prevention. HIV Testing.

  9. American Cancer Society. HPV and HPV testing.

  10. Centers for Disease Control and Prevention. Surveillance case definitions for current and historical conditions.

  11. The University of Michigan Medicine. Vaginal rashes and sores.

  12. Planned Parenthood. How long should I wait after unprotected sex to get tested for STDs?

Additional Reading

By Elizabeth Boskey, PhD
Elizabeth Boskey, PhD, MPH, CHES, is a social worker, adjunct lecturer, and expert writer in the field of sexually transmitted diseases.