What Causes a False Positive Rapid COVID Test?

With rapid tests becoming more commonplace, especially with at-home testing, it’s important to know whether or not the results are accurate. With many different variables present during the test-taking process, it is possible to receive incorrect results. This may lead to some anxiety regarding your test results. Let’s talk about rapid  COVID-19 testing and how you can ensure you received the right results.

What Is a False Positive Rapid COVID Test?

Simply put, a false positive COVID-19 test occurs when test results come back as positive, but you are actually not infected with COVID-19. If you receive a positive result, there’s a possibility that it’s inaccurate. So how do false positives happen?

What Can Cause a False Positive COVID Test?

Several factors can present a false positive COVID-19 test: 

• Taking the test too early or too late (after five days). 
• Contamination of a sample– it’s especially a risk for at-home tests. 
• Manufacturer instructions are not followed.
• Type of diagnostic test and its sensitivity.
• Quality of the lab analysis.

If you’re unsure whether or not you received a false positive test, it is advisable to confirm with a PCR test, which is considered the gold standard in COVID-19 testing. However, it is always best to consult with your healthcare provider regarding your results.

How Does a False Positive Affect You? 

A false positive affects people differently and can impact work and other responsibilities. The CDC recommends you quarantine for five days following a positive test. It is also recommended you not travel for 10 days following a positive test. 

Other precautions include keeping high-touch areas clean, washing your hands for at least 20 seconds, and wearing a well-fitting mask. If you receive a rapid test result, you should follow these instructions to ensure safety for yourself and others. If you’d like to confirm your positive test is not false, look for a BioCollections PCR testing facility near you.

Can You Receive a False Positive Rapid COVID Test After a Vaccine?

According to Dr. Hewlett at Nebraska Medicine, “Receiving the COVID-19 vaccine will not affect the PCR or antigen test results since these tests check for active disease, not immunity.” A positive Covid-19 PCR test will not be caused by mRNA-based vaccinations. If you test positive after receiving the vaccine, it’s possible you were infected either before or after your shot. It is unlikely to test false positive immediately after getting the vaccine, but ultimately it is dependent on the accuracy of the tests.

It is important to note that breakthrough cases of COVID-19 are still possible after vaccination, which can cause you to become infected. 

How Accurate Are Rapid COVID-19 Tests?

A study of over 900,000 tests concluded a 42% false positive rapid COVID test rate. However, other studies analyzed by Cochrane note false positives can be up to 72%. Of course, these numbers can be skewed by causes like contamination, analysis quality, etc. While these data points vary from study to study, rapid tests are still frequently used to determine, if an individual is positive or negative. 

Rapid tests are most accurate one to five days after symptoms begin. Positive results are most reliable within this timeframe, especially when symptoms are present. Asymptomatic individuals will also typically get accurate results, but it is again most accurate five to six days after exposure. If you are symptomatic, you should follow up a negative rapid test with a PCR test to confirm. 

How Accurate Are PCR COVID-19 Tests?

PCR tests are referred to as the “gold standard” in regards to accuracy. Most significantly, comparing a PCR test vs. a rapid test, the sensitivity of rapid antigen tests is lower than PCR and therefore less accurate. According to the same Cochrane assessment of data, the PCR test is 98% accurate. However, due to the great sensitivity and specificity of these tests, there is  a slim chance of a false positive. One study showed only a 0.2% false positivity rate. In general, PCR tests will provide you with results you can trust.

BioCollections: Accuracy Matters

Are you concerned you received an incorrect test result? At BioCollections, we offer the gold standard PCR COVID-19 test to ensure you your results are accurate. Our PCR test also evaluates a full flu panel. You can rest assured knowing what is causing your symptoms. You’ll have your results within 10-24 hours, so you won’t have to wait for the answer. Visit our website to see locations near you and schedule an appointment today.