Table of ContentsView AllTable of ContentsGenital HerpesHIVSyphilisHepatitis BSwab Test RequiredFrequently Asked Questions
Table of ContentsView All
View All
Table of Contents
Genital Herpes
HIV
Syphilis
Hepatitis B
Swab Test Required
Frequently Asked Questions
This article details which STIs can be diagnosed with a blood test and what other tests may be used to accurately detect these and other STIs.
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Options:Blood test, swab test
Herpes tests are used for people withsymptoms of genital herpes, namely visible sores, and are not recommended for those without symptoms. The only exception is if you have a sex partner withgenital herpes.
Even if there are symptoms—which tend to start four to seven days after exposure—the level of antibodies in the blood may still not be enough to be detected.
If the initial result is positive, a second test will be used to confirm the results. This second test is not a repeat of the first test. Rather, it looks for other evidence of infection in the same sample of blood. Positive results from the two tests is considered definitive proof of infection.
If there are visible sores, the healthcare professional may want to take a swab instead. This is because any viruses on the swab can be directly detected using a genetic test called anucleic acid amplification test (NAAT). The NAAT is considered the best test to determine if a person acquired the virus.
If a sexual partner is being tested and has no sores, a blood test will be used.
My Partner’s Cold Sore Gave Me Genital Herpes
Options:Blood test, saliva test, urine test
Human immunodeficiency virus(HIV) is commonly diagnosed through a blood test. The preferred tests not only detect antibodies but also proteins on the surface of the virus calledantigens.
If an initialHIV testis positive, a second test will be performed on the same blood sample to confirm the result. When confirmed, HIV tests are extremely accurate and rarely return a false result.
There are alsorapid HIV teststhat can detect HIV antibodies in blood and saliva. These tests can return results in around 20 minutes. At-home saliva-based tests are also available. However, they are less accurate, with one of 12 tests returning afalse-negativeresult (meaning that you acquired HIV even if the test says you don’t).
Urine-based HIV tests are another option, but these are not often used.
As with herpes tests, you may need to wait a while before getting tested for HIV. There is awindow periodafter infection in which tests cannot reliably detect the virus. For combination antibody/antigen tests, the window period is 18 to 45 days. For traditional antibody tests, it is 23 and 90 days.
An HIV RNA test may be performed if someone has had a recent high-risk exposure or is experiencingacute symptoms of early infection. It’s a blood-based test that can detect the HIV-virus as early 10 days after infection—sooner than other forms of testing.
What Tests Can Diagnose HIV?
Options:Blood tests, swab test, spinal fluid test
Treponemal tests are a group of tests that can detect syphilis antibodies in the blood. If positive, a second test to detect nontreponemal antibodies can confirm the results. These antibodies are related to the damage the bacteria cause to cells.
A nontreponemal test can also establish the stage of infection based on the level of antibodies in the blood, called the titer. Based on whether the titer is increasing or decreasing, a healthcare provider can tell if treatment is working or if you have been reinfected.
Syphilis can also be detected from a swab of a sore or with a sample of spinal fluid.
The average window period for syphilis is around three to six weeks after infection.
How Syphilis Is Diagnosed
Option:Blood tests
As with syphilis, there are multiple blood tests forhepatitis B. These can be used to determine your history of infection. They can also determine whether you’re currently infected.
The diagnosis of hepatitis B involves different blood tests that detect an antigen called hepatitis B surface antigen (HBsAg), as well as two antibodies called hepatitis B surface antibody (HBsAb) andhepatitis B core antibody (HBcAb).
Each test can tell your healthcare provider different things:
The window period for hepatitis B can range from 60 to 150 days.
How Hepatitis B Is Diagnosed
In some cases, a swab may be used to culture (grow) the bacteria in a lab. In others, the cells on the swab may be genetically tested to confirm the presence of the STI.
Self-swabs can be a big help for people who have histories ofsexual traumaor those who are simply reluctant to have a stranger touch their bodies. If you’re worried about a swab test and need one, talk to your healthcare provider. In some cases, you may be able to take the swab yourself.
Summary
Some people avoid STI screening due to the discomfort or embarrassment of having a genital swab. But, today many STIs can be diagnosed with blood tests, including genital herpes, HIV, syphilis, and hepatitis B.
Even so, STIs like chlamydia, gonorrhea, and trichomoniasis require a swab for diagnosis. Swabs are also an option for syphilis and herpes.
Here’s how long it takes for various STIs to show up on a blood test after exposure:Hepatitis B:Three to six weeksHepatitis C:Two to six monthsHerpes:One to four monthsHIV:Two to six weeksSyphilis:One to three months
Here’s how long it takes for various STIs to show up on a blood test after exposure:
As with blood tests, a positive urine or swab test result after exposure will vary depending on the STI in question:Chlamydia and gonorrhea: One to two weeksHIV: One to three monthsTrichomoniasis: One week to one month
As with blood tests, a positive urine or swab test result after exposure will vary depending on the STI in question:
11 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Centers for Disease Control and Prevention.Genital herpes screening.Workowski KA, Bachmann LH, Chan PA, et al.Sexually transmitted infections treatment guidelines, 2021.MMWR Recomm Rep.2021;70(4):1-187. doi:10.15585/mmwr.rr7004a1National Institutes for Health.HIV overview: HIV testing.Food and Drug Administration.Information regarding the OraQuick in-home HIV test.Centers for Disease Control and Prevention.Getting tested for HIV.Centers for Disease Control and Prevention.Syphilis.Wilkins T, Sams R, Carpenter M.Hepatitis B: screening, prevention, diagnosis, and treatment.Am Fam Physician.2019;99(5):314-323.Centers for Disease Control and Prevention.Clinical overview of hepatitis B.Catarino R, Vassilakos P, Bilancioni A, et al.Randomized comparison of two vaginal self-sampling methods for human papillomavirus detection: dry swab versus FTA cartridge.PLoS One.2015;10(12):e0143644. doi:10.1371/journal.pone.0143644Centers for Disease Control and Prevention.Getting tested for STIs.University of Oregon Health Center.STI screening timetable.
11 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Centers for Disease Control and Prevention.Genital herpes screening.Workowski KA, Bachmann LH, Chan PA, et al.Sexually transmitted infections treatment guidelines, 2021.MMWR Recomm Rep.2021;70(4):1-187. doi:10.15585/mmwr.rr7004a1National Institutes for Health.HIV overview: HIV testing.Food and Drug Administration.Information regarding the OraQuick in-home HIV test.Centers for Disease Control and Prevention.Getting tested for HIV.Centers for Disease Control and Prevention.Syphilis.Wilkins T, Sams R, Carpenter M.Hepatitis B: screening, prevention, diagnosis, and treatment.Am Fam Physician.2019;99(5):314-323.Centers for Disease Control and Prevention.Clinical overview of hepatitis B.Catarino R, Vassilakos P, Bilancioni A, et al.Randomized comparison of two vaginal self-sampling methods for human papillomavirus detection: dry swab versus FTA cartridge.PLoS One.2015;10(12):e0143644. doi:10.1371/journal.pone.0143644Centers for Disease Control and Prevention.Getting tested for STIs.University of Oregon Health Center.STI screening timetable.
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Centers for Disease Control and Prevention.Genital herpes screening.Workowski KA, Bachmann LH, Chan PA, et al.Sexually transmitted infections treatment guidelines, 2021.MMWR Recomm Rep.2021;70(4):1-187. doi:10.15585/mmwr.rr7004a1National Institutes for Health.HIV overview: HIV testing.Food and Drug Administration.Information regarding the OraQuick in-home HIV test.Centers for Disease Control and Prevention.Getting tested for HIV.Centers for Disease Control and Prevention.Syphilis.Wilkins T, Sams R, Carpenter M.Hepatitis B: screening, prevention, diagnosis, and treatment.Am Fam Physician.2019;99(5):314-323.Centers for Disease Control and Prevention.Clinical overview of hepatitis B.Catarino R, Vassilakos P, Bilancioni A, et al.Randomized comparison of two vaginal self-sampling methods for human papillomavirus detection: dry swab versus FTA cartridge.PLoS One.2015;10(12):e0143644. doi:10.1371/journal.pone.0143644Centers for Disease Control and Prevention.Getting tested for STIs.University of Oregon Health Center.STI screening timetable.
Centers for Disease Control and Prevention.Genital herpes screening.
Workowski KA, Bachmann LH, Chan PA, et al.Sexually transmitted infections treatment guidelines, 2021.MMWR Recomm Rep.2021;70(4):1-187. doi:10.15585/mmwr.rr7004a1
National Institutes for Health.HIV overview: HIV testing.
Food and Drug Administration.Information regarding the OraQuick in-home HIV test.
Centers for Disease Control and Prevention.Getting tested for HIV.
Centers for Disease Control and Prevention.Syphilis.
Wilkins T, Sams R, Carpenter M.Hepatitis B: screening, prevention, diagnosis, and treatment.Am Fam Physician.2019;99(5):314-323.
Centers for Disease Control and Prevention.Clinical overview of hepatitis B.
Catarino R, Vassilakos P, Bilancioni A, et al.Randomized comparison of two vaginal self-sampling methods for human papillomavirus detection: dry swab versus FTA cartridge.PLoS One.2015;10(12):e0143644. doi:10.1371/journal.pone.0143644
Centers for Disease Control and Prevention.Getting tested for STIs.
University of Oregon Health Center.STI screening timetable.
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