Throat swab, rapid strep test, rapid antigen 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.
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.
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 requires taking 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:
Influenza (flu) test
Mononucleosis (mono spot) test
Test results may vary depending on your age, gender, health history, the method used for the test, and other things. Your test results 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.
The rapid strep screen requires taking 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.
This test poses no known risks.
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.
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.