How Accurate Are At-Home STI Tests Compared to Clinic Tests?

By Amy Harris, MS, RN, CNM

You care about your sexual health and want to keep sexually transmitted infections (STIs) out of your sexual relationships and the bedroom, but you only have a limited number of healthcare dollars to spend. Of course, you want to get your money’s worth when choosing which type of STI test to purchase. After all, who wants to pay for a test you couldn’t be sure is accurate? That would be a waste of your precious healthcare dollars.

As an informed healthcare consumer who does their research, here are the facts on the accuracy of at-home STI tests compared to those conducted in clinics. Everlywell wants you to have all of the information you need to make an informed choice about the best type of STI testing for you.

STI Test Basics: What’s Available?

Bacteria, viruses, and microscopic parasites can cause STIs. Nearly all of these require a microscope to be seen. So, aside from noticing any symptoms—and not all STIs cause easily noticed symptoms—laboratory tests (lab tests) are the only way to know whether or not you have an STI. Fortunately, there are tests for nearly all STIs.

The lab tests for STIs include:

• Blood Tests: To diagnose syphilis, HIV, herpes, hepatitis B, and Hepatitis C.

• Urine Tests: To diagnose gonorrhea, chlamydia, and trichomoniasis.

• Swab Tests: Collect a swab sample of the inside of your penis, vagina, or rectum to diagnose herpes, gonorrhea, chlamydia, chancroid, lymphogranuloma venereum (LGV), and human papilloma virus (HPV).

How Do You Know Which STI Tests You Need?

The easy answer is that everyone who is sexually active and at risk for an STI should be tested. The kinds of STD tests you need can depend on your risk factors. Examples of risk factors for STIs are:

• Age (younger people have more STIs than older people)

• Having a new sexual partner

• Having more than one sexual partner

• Being assigned male at birth and having sex with others assigned male at birth

• Having been forced to have sex against your will

• Having HIV

• Living in a higher-risk situation, such as in a jail

What Is the Difference Between Testing and Screening for STIs?

Testing for an STD or sexually transmitted infection in someone who doesn't have symptoms is called screening. People screen for STIs to reduce the chances that they will accidentally pass an infection on to their sexual partners.

Testing is used to diagnose which STI a person might have when they have:

• Symptoms of an STI

• Concerns about being exposed to an STI

Screening for STIs is a good idea because not all STIs cause symptoms. Other STI symptoms aren’t always obvious and can come and go. Or, some STIs, such as syphilis and herpes, can have overlapping symptoms, making self-diagnosis risky.

Ignoring subtle STI signs and symptoms can potentially lead to more serious problems, such as pelvic pain, infertility, or cancers caused by HPV. Both testing and screening can ensure you receive the treatment you need and don’t spread STIs.

What STI Tests Can I Take at Home?

At-home testing kits are an attractive option for people without medical insurance and those without easy access to a healthcare provider. At-home tests are also sometimes called point-of-care tests. However, some point-of-care tests can be done at clinics or laboratories. These are called in-person tests.

Currently, at-home tests are available for:

• HIV

• Chlamydia

• Gonorrhea

• Syphilis

• Hepatitis C

• Trichomoniasis

Everlywell offers all of these at-home STI tests on their website so that you can order them directly and have them shipped to you with maximum convenience and confidentiality. They also offer the following in-person STI tests at Quest laboratoryⓇ sites:

• STD Screening Panel - Basic, which tests for HIV, syphilis, gonorrhea, and chlamydia.

• Combined Gonorrhea and Chlamydia.

• HIV 1 and 2, with same-day results.

After ordering a test online, you can go to the QuestⓇ laboratory site most convenient for you. Except for the in-person HIV test (with results back the same day), you’ll have your results digitally (no embarrassing mail or suspicious phone calls) in 1-2 days. In-person testing works for people who want to test as quickly as possible or would like help collecting the blood sample for the test.

How Does the Accuracy of At-Home Tests Compare to Clinic Tests?

The accuracy of STI tests varies depending on what type of infection you are testing for and what kind of test you use.

There are two key parts of a test’s accuracy. They are:

• Sensitivity

• Specificity

Sensitivity and specificity tell you how well a test works. Sensitivity is the ability of the test to correctly identify individuals with the condition. Specificity is the ability to correctly identify those without the condition. There is usually a trade-off between the two.

Ideally, STI tests would have both a high sensitivity (meaning that everyone with an STI tests positive when tested) and a high specificity (meaning that everyone who tests negative does not have an STI). STI tests aim to:

• Have high sensitivity and specificity values (as close to 100 percent as possible)

• And be reliable (consistent in producing accurate results over multiple tests)

Unfortunately, it is nearly impossible to have a 100% accurate test. This is partly because of:

• Possible user error, such as not getting enough blood or fluid, or swabbing the incorrect area

• Possible operator error (the laboratory makes a mistake in processing or reading your test result)

• Equipment error

• A low-quality specimen

Given this, user error may be higher with at-home STI tests, making them less accurate. Other circumstances limiting how accurate your test might be are:

• Timing. If you’ve been recently infected, it's possible to have a negative result but still be infected with a sexually transmitted infection.

• Contamination. It is important to wash and dry your hands before collecting your sample for this reason. The presence of sexual lubricants, menstrual blood, or vaginal or rectal medications could all influence test results.

Modern HIV tests are highly accurate, but the timing of when you take the test matters. The different types of HIV tests available are:

• Nucleic acid amplification tests (NAATs) detect the virus as early as 10-33 days post-exposure. The OraQuickⓇ In-Home HIV Test has a reported sensitivity of 92% and specificity of 99.98%. It still should only be used as a screening test, meaning that if your Oraquick test is positive, you should have the result confirmed with a blood test.

• Antigen/antibody tests will detect HIV in your blood 18-45 days after exposure for blood draw tests or 18-80 days after exposure for finger-prick tests.

• Antibody tests (rapid and at-home tests), which look for the body’s immune response, take 23-90 days to become reliable.

For chlamydia and gonorrhea, Nucleic Acid Amplification Tests (NAATs) have the highest sensitivity and specificity. These tests are highly accurate, with sensitivity and specificity rates of 90% or higher for both infections for both urine and swabs.

The VisbyⓇ test, offered by Everlywell, tests for gonorrhea, chlamydia, and trichomoniasis. It is only available for people assigned female at birth, is an at-home test, and gives results in 30 minutes or less. The test is 98% accurate.

What Does a Positive or Negative STI Test Result Mean?

A positive test result means that you have an STI and should be treated. A negative test means you didn’t have that STI at the time of the test.

Even if you have a negative test, it is important to undergo regular STI testing if you are sexually active and not in a mutually monogamous relationship (neither you nor your partner has sex with other people). Depending on the number of sexual partners you have, you may want to be screened once a year or more often.

Accurate At-Home STI Testing Options From Everlywell

With Everlywell, STI testing can be as quick and easy as a swab, peeing in a cup, or a finger prick. Lab testing is easy and convenient with at-home collection and digital results in days.

It may be helpful to speak with an STI healthcare provider to make sense of your symptoms, understand what STIs you might be at risk for, or how to choose the best test for you. Virtual healthcare visits through Everlywell can provide you with the answers you want, without you even having to leave your home. Fast, easy, and discreet, providers will develop a personalized care plan for you, which could include testing, lifestyle recommendations, and prescriptions if needed.