Strep Throat, Group A Streptococcus

This is a test to determine if a sore throat (pharyngitis) or tonsil infection (tonsillitis) is caused by a Group A streptococcal bacteria (strep throat).

The test identifies Streptococcus pyogenes, known as Group A streptococcus, which are bacteria (a type of germ) that infect the back of the throat and cause the common infection called strep throat.


A swab is brushed against your throat and tonsils. The swab is tested in your doctor's office or may be sent to a laboratory.


Normal values are negative for strep.

Ranges for normal findings may vary among different laboratories and hospitals. You should always check with your doctor after having lab work or other tests done to discuss the meaning of your test results and whether your values are considered within normal limits.


A positive rapid test indicates the presence of group A streptococci, the bacteria that cause strep throat. A negative rapid test indicates that you probably do not have strep throat. If negative, your caregiver may have the sample tested by doing a second test called a culture (a test that grows bacteria taking from the throat). This second test is done to be sure that there is no group A strep in your throat. Culture results may take one or two days. Recent antibiotic therapy or gargling with some mouthwashes before the rapid test may make the test wrong.

Your caregiver will go over the test results with you and discuss the importance and meaning of your results, as well as treatment options and the need for additional tests if necessary.


It is your responsibility to obtain your test results. Ask the lab or department performing the test when and how you will get your results.