Advantages and Accuracy of Rapid STI Tests

Rapid sexually transmitted infection (STI) tests were designed to save people time, effort, and stress when being evaluated for gonorrhea, chlamydia, human immunodeficiency virus (HIV), and other infections passed through sexual contact.

Some rapid STI tests are performed in a doctor's office or clinic while others can be done in the comfort and privacy of your home.

These tests aim to avoid one of the most common problems STI clinics encounter: people who fail to return for their test results. It's a sad fact of life for people who work in such clinics—seeing people who are worried enough to get tested but are too scared to face the results.

Because of this, infections can be left untreated, increasing the risk of complications and the chance of the infection spreading to other people.

This article discusses the advantages and disadvantages of at-home STI testing. It also looks at the accuracy of these tests and what to do if you get a positive test result.

What Infections Can Rapid Tests Detect?

At-home testing is available for a number of STIs, including:

• Chlamydia: This STI may not cause symptoms, so often the only way to know you have it is to be tested. In females, undiagnosed chlamydia can lead to conditions like pelvic inflammatory disease (PID) or infertility. Early detection and treatment can prevent these long-term complications. 
• Gonorrhea: Gonorrhea doesn't always cause symptoms. In females, symptoms can be mild and easy to dismiss. When gonorrhea goes untreated, however, it can lead to long-term problems like PID in females and problems with the prostate and testicles in males. This is why it is important to get tested and treated right away.
• Hepatitis B (HBV): The CDC recommends HBV testing for certain individuals. These include people born in countries with high HBV rates, people who inject drugs, blood and tissue donors, and people with certain conditions like HIV and end-stage renal disease. 
• Herpes simplex: The CDC doesn't recommend testing in people without symptoms. This is because people who don't have symptoms often don't change their sexual behavior. If you do have symptoms, testing can give you important information that can help stop you from spreading herpes to your sexual partners.
• HIV: HIV testing can help prevent the spread of the HIV virus and ensure you get treatment for the disease. Treatment can reduce your viral load so you stay healthy and avoid passing the virus on to others. At-home testing is done using an oral swab.
• Human papillomavirus (HPV): Your healthcare provider can perform an HPV test to screen for cervical cancer. At this time, the CDC doesn't recommend screening for males or females under the age of 30. At-home tests look for certain high-risk strains of the virus that are associated with cervical cancer. If you test positive, following up with your healthcare provider can ensure you're closely monitored for precancerous lesions and that you receive any necessary treatment. 
• Syphilis: You should get a syphilis test if you have symptoms, if you have a sexual partner who was recently diagnosed, or if you are at high risk for getting the infection. Untreated, syphilis can progress over time and cause permanent damage to your brain, nerves, heart, and other parts of your body. Because the early-stage symptoms are mild, you may not know you're infected and can easily spread the virus to others. 

Accuracy of Rapid STI Tests

Not all rapid tests are created equal. Some have higher sensitivity and specificity than others.

• Sensitivity is how well a test can detect true positives (in other words, the percentage of cases the test correctly identifies).
• Specificity is how reliable a positive result is (the percentage of positive results that are accurate).

When testing during acute infection, rapid STI tests offer the following sensitivities and specificities, on average:

• Chlamydia: 86% sensitivity, 97% specificity
• Gonorrhea: 86% sensitivity, 97% specificity
• Hepatitis B: 97% sensitivity, 99% specificity
• Herpes simplex: 93% sensitivity, 99.9% specificity
• HIV (at-home, oral swab): 92% sensitivity, 99% specificity
• Human papillomavirus (HPV): 87% sensitivity, 94% specificity
• Syphilis: 85% sensitivity, 91% specificity

Advantages

A rapid STI test allows you to get your results in minutes rather than days. For some people, at-home testing may also be preferable because it can be done in private and avoids the potential embarrassment of testing in a clinic.

If the test is positive (meaning you've been infected), you can get immediate treatment. With diseases like HIV, this is important since early treatment translates to a lower risk of illness and a longer lifespan.

The newer tests also aim to overcome another factor that keeps many people away: needles and blood. Depending on the disease, a rapid test may only require a swab of body fluid or a urine sample.

Disadvantages

Unfortunately, a lower sensitivity rate translates to an increased risk of a false-negative result. This means a person is told they do not have the infection when they actually are infected.

For perspective, the 92% sensitivity rate of the currently available at-home HIV test translates to one false negative out of every 15 tests. This is why certain bacterial diseases (like syphilis, gonorrhea, and chlamydia) are more accurately diagnosed with a lab culture rather than a rapid test.

Confirming Your Results

If you test positive for an STI with an at-home test, the next step is to contact your healthcare provider. You will probably need another test to confirm your results. If the second test also comes back positive, you will need to begin treatment right away. 

Summary

At-home STI tests are a way to quickly find out if you have been infected with chlamydia, gonorrhea, or a number of other sexually transmitted infections. These tests can be done in the privacy of your home and can give you fast results.

Unfortunately, at-home STI tests are not as accurate as those conducted by a healthcare provider. It is possible to test negative even if you are infected. Talk to your healthcare provider about any concerns you have before or after self-testing.

A Word From Verywell

At-home tests can fail for many reasons besides just the technical limitations of the tests themselves. For example, improper swabbing can cause a false negative result. Testing outside of the window period may also cause a false negative result. This means the person was infected but that it was too soon for it to be detected on the test.

For these reasons, any positive, inconclusive, or suspicious negative result from an at-home test should be followed up with an in-office test at your local clinic or healthcare provider's office.