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Mar 1, 2024 · A brief report published last week in the New England Journal of Medicine found that in a group of 11,297 people who tested themselves for COVID every 48 hours for 15 days, about 1.7% received at least one false-positive result on a rapid test—even though they had negative molecular tests done at the same time.
- Overview
- What causes a false positive rapid COVID-19 test?
- How accurate are rapid COVID-19 tests?
- How to reduce the risk of a false positive
- When to take a rapid test
- What to do if you get a positive result
- Summary
A false positive result is possible with a rapid COVID-19 test. It happens when a person does not have COVID-19 but still tests positive for the disease.
People can use a rapid COVID-19 test at home to check whether they have SARS-CoV-2, the virus that causes COVID-19. The result is available within a few minutes.
These self-tests do not require laboratory analysis, and people can use one whether or not they are vaccinated or have any symptoms.
Rapid tests are available online, in pharmacies, or in retail stores. Other terms for a rapid test include a home test, an at-home test, or an over-the-counter (OTC) test.
Learn more about at-home COVID-19 tests.
This article outlines how a false positive on a rapid COVID-19 test can happen. It also discusses other factors, such as test accuracy and steps people should take if they test positive for COVID-19.
Although a rapid COVID-19 test is unlikely to produce a false positive result, possible reasons for inaccurate results include:
•Symptoms and testing time: Rapid tests tend to be more accurate if a person tests while experiencing some symptoms.
•Contamination: The Food and Drug Administration (FDA) explains that false positive results can occur due to contamination.
•Not reading instructions: People should read the package instructions before using an at-home COVID-19 test. A person may get a false positive result if they check the result before or after the test instructions recommend doing so.
According to the World Health Organization (WHO), rapid tests are less accurate than polymerase chain reaction (PCR) tests, which detect a virus’s genetic material. PCR tests check whether a person has the virus at the time they get tested and can provide an early diagnosis.
However, a rapid test has other advantages, which may outweigh the importance of sensitivity. These advantages include the below:
•They are more easily available.
•The results are ready faster.
•They are cheaper and easier to do, making them suitable for frequent use.
A positive result on an at-home COVID-19 test is usually accurate, but false negatives can occur when a person has no COVID-19 symptoms or their infection happened recently.
A person can take some measures to reduce the risk of getting a false positive test result, such as:
•buying FDA-approved at-home tests
•following the directions on the package
•avoiding using expired tests
•not sharing or reusing swabs
The FDA also provides a list of antigen tests that people can buy. These include:
The Centers for Disease Control and Prevention (CDC) recommend people take a rapid test if they:
•have developed COVID-19 symptoms, such as cough, fatigue, shortness of breath, or nasal congestion
•have been in close contact with someone who has contracted SARS-CoV-2
•are attending an indoor or crowded event
If a person gets a positive result after an at-home test, they likely have COVID-19. If someone tests positive, the CDC recommends taking the following precautions:
•staying at home for 5 days and avoiding close contact with others
•staying hydrated
•seeking medical care if an individual has trouble breathing
•getting enough rest
The WHO recommends calling a medical professional if a person tests positive, has mild symptoms, and is at risk of developing a serious disease.
A rapid or at-home COVID-19 test is a quick and convenient way to find out if a person has COVID-19.
Rarely, rapid tests may provide a false positive result. For example, if someone does not follow the package instructions, they may get inaccurate results.
Jun 5, 2023 · For people without symptoms, there’s a higher chance of getting a false negative result compared to people with symptoms. On the other hand, rapid tests give a false positive less than 1...
- Daniel Yetman
Sep 22, 2023 · False positive COVID-19 tests —when your result is positive, but you aren’t actually infected with the SARS-CoV-2 virus—are a real, if unlikely, possibility, especially if you don’t...
Feb 21, 2024 · False positive tests were classified as incidental false positives (in participants with at least one negative rapid antigen test during the study period) or persistent false positives...
How accurate are rapid antigen tests for diagnosing COVID-19? Read podcast transcript and more. . Key messages. • Rapid antigen tests are most accurate when they are used in people who have signs or symptoms of COVID-19, especially during the first week of illness. People who test negative may still be infected.
