Strep throat
Disease Information
Tests
How is strep throat diagnosed in children?
If a strep throat infection is suspected a rapid strep test or a throat culture is necessary to confirm the diagnosis.
Rapid strep test
- During a rapid strep test, the doctor rubs a cotton swab in the back of the mouth and over both tonsils to collect a sample of bacteria from the infected area. This can be done in the doctor’s office.
- Within a few minutes, the test determines whether group A Streptococcus bacteria are present in the child’s throat.
- Although generally reliable, rapid strep tests are not always 100 percent accurate. They can sometimes produce a “false negative” and show no sign of bacterial infection when strep is actually there.
Throat culture
- If the rapid test comes back negative but the child shows signs of strep, the sample may be sent to the lab for a throat culture. A throat culture may also be done instead of a rapid strep test.
- A throat culture means that the cotton swab sample will be put on a special plate that allows group A Streptococcus bacteria to grow. If bacteria do not grow, the child does not have group A Streptococcus in the throat
Carriers of strep throat
Group A Streptococcus can live in the nose and throat of some people without causing an infection. These people are called carriers. It’s not always easy to know who is a carrier; doctors usually make this diagnosis on a case-by-case basis.

