A person’s immune system may make it difficult for a blood test to show the presence of a sexually transmitted disease. That’s why doctors use a swab sample or urine test for certain STDs.

STI screening is important to catch infections early and start treatment before they lead to serious health complications. However, many people who have STIs don’t have any symptoms and go undiagnosed.

Herpes

Herpes is a very common virus that can be passed from person to person. There is no cure for herpes, but antiviral medications can help control outbreaks and reduce the severity of symptoms.

Herpes symptoms include fever, itching, swollen glands, and sores that can occur in different locations. Symptoms usually begin within 2 to 12 days of exposure to the herpes virus and often resolve in 6 to 10 days.

A normal blood test can detect herpes infection in asymptomatic people, but the rate of false positives is much higher than with other STIs like chlamydia and gonorrhea. For that reason, herpes tests are recommended only for people with herpes symptoms or a high risk of herpes.

Chlamydia

Chlamydia is a bacterial infection that can be detected using a normal blood test. The test looks for chlamydia antibodies that can be produced by the body in response to a chlamydia infection.

The results of the test are reported as positive or negative – a positive means that you have chlamydia. However, a positive result can also be a false-positive, which means that you have antibodies that are the result of a past chlamydia infection.

If you have chlamydia, you should see your doctor as soon as possible. Your doctor can prescribe antibiotic medicine that will help your body get rid of the infection. Treatment will not only make you and your partner(s) healthy, but it will stop you from spreading the infection to others.

Gonorrhea

Gonorrhea is a sexually transmitted disease (STD). The bacteria that cause gonorrhea are spread during vaginal, anal or oral sex. This infection is especially common in young adults.

A normal blood test can help doctors detect gonorrhea in women. This test also can help diagnose chlamydia and other STDs.

Gonorrhea is a very common infection that can affect the urethra, rectum, throat, and joints. It can lead to serious long-term health problems if left untreated, including pelvic inflammatory disease in women and infertility in men.

Syphilis

Syphilis is a sexually transmitted infection (STI). It can be passed from skin-to-skin contact during vaginal, anal or oral sex, and from sharing sex toys with people who are infected.

Early stages of syphilis are often unnoticed, but they can cause serious long-term damage to the body. They usually start with a sore called a chancre that appears at the site of the infection.

If you think you may have syphilis, make an appointment with your GP or local sexual health services. They can test you for it with a normal blood test.

The only certain way to prevent syphilis is to abstain from having sex. You can also lower your risk of getting it by using a condom during sex.

Human Papillomavirus

Human papillomavirus, or HPV, is a group of more than 100 different types of related viruses that are spread by sexual contact. Some are harmless, but others can cause genital warts and cervical cancer.

Almost everyone is exposed to HPV. Many of these infections go away on their own, and some never lead to any problems at all.

However, around 13 of the 200 known HPV types can cause cervical cancer and other cancers of the anus, vulva or penis.

Doctors recommend a Pap smear test or co-test to find abnormal cells that could signal cervical cancer, or other HPV-related problems. This screening is also helpful for people under 30 who might have a higher risk for HPV-related health issues.