Rapid tests, also known as rapid diagnostic tests or RDTs, are easy-to-use tests that provide quick results, usually in 20 minutes or less. Unlike most standard tests, which have to be sent to a lab, rapid tests are done and provide results at the point of care. The point of care is the place where you are getting care. It can include your provider’s office, a clinic, or even your own home.
Rapids tests usually include the following steps:
- You will provide a sample of your body fluid, such as blood, urine, saliva, or nasal secretions.
- The sample is mixed with a special substance that will cause a chemical reaction if a disease or other condition is present.
- Results will show on a dipstick or rapid test cassette.
- A dipstick is a thin, plastic strip that’s coated with chemicals. If the test is positive, the dipstick will change colors when placed in the sample.
- A rapid test cassette is a small, plastic case that has a well that holds the sample. The well will show a letter or a symbol to indicate the result.
Most rapid tests are highly accurate, but the results are not always as accurate as standard lab tests.
Other names: rapid diagnostic tests, RDT’s point-of-care tests
How are they used?
Rapid tests are most often used to diagnose infectious diseases, including:
- Strep throat
- COVID 19. Rapid tests for COVID-19 usually provide results in about 30 minutes.
Rapid tests are also used in certain home-based tests, such as pregnancy tests.
What are the advantages and disadvantages of rapid tests?
The advantages of rapid tests include:
- Fast results. This may allow you to get treatment faster. Faster treatment can reduce the severity of your symptoms, and may help prevent the spread of disease
- Easy to use. They can be done by non-medical workers and volunteers who have been trained to do the test. You may even be able to perform a rapid test on yourself.
- Little or no special equipment required. This is especially useful in areas with limited resources or access to specialized labs.
Disadvantages of rapid tests:
- Lower sensitivity than lab tests. Sensitivity means how well a test can identify a disease or condition. Rapid tests are not as good as lab tests at finding diseases in the earliest stages of infection.
- False negatives are more common. A false negative result means your test shows you don’t have a disease or condition, but you actually do have it.
Providers will often take a second sample and send it to a lab for testing to confirm or rule out the results of a rapid test. But you may be able to get treatment and help prevent the spread of disease while you wait for lab results.
Is there anything else I need to know about rapid tests?
Home based rapid tests are available for COVID-19. Like other rapid tests, the rapid COVID-19 tests have lower sensitivity than standard lab tests. But getting fast, home-based results may help prevent the spread of disease. Talk to your health care provider to learn more about these home-based tests.
Courtesy of MedlinePlus from the National Library of Medicine.