Strep Screen (Rapid)
Does this test have other names?
Throat swab, rapid strep test, rapid antigen test
What is this test?
The rapid strep screen is used to test for bacteria called group A streptococcus.
Group A streptococcus bacteria cause illnesses, such as strep throat and scarlet fever—a
rash that may happen after a case of strep throat. Strep throat and scarlet fever
can cause a number of symptoms, particularly a fever and a sore throat. These illnesses
are quite contagious and need antibiotics to treat.
Healthcare providers have two ways to test for group A streptococcus. For the rapid
strep screen, your healthcare provider or a nurse takes a sample of cells from your
tonsils and back of the throat and tests it right in the healthcare provider's office.
You can get your results in as little as 5 minutes. If the rapid strep screen is positive,
you have strep throat and no further tests may be needed.
Why do I need this test?
You may need this test if your healthcare provider suspects that you have strep throat.
Symptoms of strep throat can include:
Painful or difficult swallowing
Swelling or tenderness of the glands in the neck
Nausea or vomiting
Lack of appetite
Tonsils that are swollen and red
Patches of white on the tongue or throat
You may need this test to confirm you have a bacterial infection instead of a viral
infection before a healthcare provider will prescribe antibiotics. You may also need
this test if the results of a throat culture, which can provide a more accurate diagnosis,
are unavailable for a few days.
What other tests might I have along with this test?
If the rapid strep screen is negative, your healthcare provider may do another test
called throat culture to make sure that strep is not the cause of your sore throat
and other symptoms. This test also needs a swab of cells from your tonsils or back
of the throat. The sample is sent to a lab, where it is grown, or cultured, and tested
for strep bacteria. The results are available in about 2 days. Your results will reveal
whether you have group A streptococcus.
Your healthcare provider may also order:
What do my test results mean?
Test results may vary depending on your age, gender, health history, and other things.
Your test results may be different depending on the lab used. They may not mean you
have a problem. Ask your healthcare provider what your test results mean for you.
Your test results will show whether you have group A streptococcus bacteria in the
cells or mucus of your throat. A normal (negative) result will not show any group
A streptococcus bacteria. If the test is positive, that means bacteria have been found
and you likely have strep throat.
How is this test done?
The rapid strep screen needs a swab of mucus or cells from the back of your throat.
The healthcare provider, nurse, or lab technician will gently swipe the back of your
throat with a long cotton swab. A second sample may be taken at the same time to be
used in a throat culture if the rapid strep screen is negative.
Does this test pose any risks?
This test poses no known risks.
What might affect my test results?
Nothing is likely to affect the results of your test, as only the presence of group
A streptococcus bacteria should give you a positive result.
How do I get ready for this test?
You don't need to prepare for this test. Be sure your healthcare provider knows about
all medicines, herbs, vitamins, and supplements you are taking. This includes medicines
that don't need a prescription and any illicit drugs you may use.