STDs Detected by Blood Tests

Testing for sexually-transmitted diseases (STDs) is an important part of keeping up with sexual health, but one of the reasons people avoid testing is a fear of embarrassing or uncomfortable swabs. Luckily, testing technology has evolved greatly and many STDs can be detected via blood or urine testing.

Urine tests are primarily used to detect chlamydia and gonorrhea, while blood tests are widely available for the following STDs:

Herpes

There are a number of herpes blood tests on the market. That said, their accuracy is somewhat variable.

Because of this, confirmatory testing with a secondary method is needed before interpreting the results. The U.S. Centers for Disease Control and Prevention recommends with Biokit or Western blot as the secondary confirmatory tests.

The downside of herpes blood tests is both HSV-1 and HSV-2 strains can infect the mouth and genitals. The blood test cannot determine the location of the infection in the absence of visible sores.

The herpes virus can be transmitted even when no symptoms are present. That can lead to some painful conversations when a newly infected person thinks they've been lied to by the person they love. They may not believe that the person who infected them had no idea they had herpes.

HIV

HIV is usually diagnosed through a blood test. There are also oral tests that use saliva samples to test for the virus that causes AIDS. In general, it requires both a positive initial test and a positive confirmatory test for a person to be considered HIV-positive.

Doctor examining blood test.

However, the process of confirmatory testing is usually invisible. Both tests are generally done on the same blood sample.

When you get your results, it doesn't necessarily show what tests were done on your blood. It only shows what the test results were in combination.

Syphilis

There are several different blood tests for syphilis. These are used in combination to determine whether you are currently infected. They can also determine whether you have ever been infected in the past.

Hepatitis B

As with syphilis, there are multiple blood tests for hepatitis. These can be used to determine your history of infection. They can also determine whether you're currently infected with the virus.

Cultures

If neither urine nor a blood test is available for an STD, then it is usually identified by either visual or microscopic examination of sores or by some form of bacterial culture. These types of tests may also be used instead of, or in addition to, blood tests for the diseases listed above in certain situations.

Taking cultures of herpes sores can be a more effective way to determine the virus location and specific strains than a blood test. That's not true in all situations as the timing of testing is critical. But it can be a better choice if people visit their healthcare provider early in an outbreak. 

The Use of Self-Swabs in STD Testing

If you’re worried about a swab test and need one, talk to your healthcare provider. It’s possible that you may be able to take the swab yourself. That won’t fix the problem for everyone.

Self-swabs can be a big help for people who have histories of sexual trauma or those who are simply reluctant to have a stranger touch their body in what feels to them like an intimate way.

Not all healthcare providers will allow people to do self-swabs, but they have been shown to be effective for detecting many STDs. If nothing else, it’s better to have a self-swab test than no test at all.

Frequently Asked Questions

  • Can some STDs show up in regular blood panels?

    STD blood tests are not the same tests that appear in a regular blood panel. You need a separate blood test for STDs and this is not routinely ordered by a healthcare provider unless requested.

  • How long does it take for STDs to show up in blood test after exposure?

    Here's how long it takes after exposure for various STDs to show up on a blood test:

    • Syphilis: one to three months
    • HIV: two to six weeks
    • Herpes: one to four months
    • Hepatitis B: three to six weeks
    • Hepatitis C: two to six months
  • How long does it take for STDs to show up in urine or swab tests after exposure?

    As with blood tests, a positive urine or swab test result after exposure will vary depending on the STD in question:

    • Chlamydia and gonorrhea: one to two weeks
    • HIV: one to three months
    • Trichomonas: one week to one month
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5 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.
  1. Centers for Disease Control and Prevention. Genital Herpes Screening FAQ. Updated February 9, 2017.

  2. U.S. Centers for Disease Control and Prevention. Sexually Transmitted Infections Treatment Guidelines, 2021. MMWR. Published July 23, 2021.

  3. Catarino R, Vassilakos P, Bilancioni A, Vanden Eynde M, Meyer-Hamme U, Menoud PA, Guerry F, Petignat P. Randomized Comparison of Two Vaginal Self-Sampling Methods for Human Papillomavirus Detection: Dry Swab versus FTA Cartridge. PLoS One. 2015 Dec 2;10(12):e0143644. doi: 10.1371/journal.pone.0143644.

  4. Centers for Disease Control and Prevention. Who should get tested for STDs?

  5. University of Oregon Health Center’s STI Screening Clinic. STI screening timetable.

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