What It Is
A rapid strep test involves a quick throat swab. Within minutes, the test can show the presence of group A streptococcus bacteria, which can cause strep throat and other infections (including scarlet fever, abscesses, and pneumonia).
Strep throat is a bacterial infection that affects the back of the throat and the tonsils, which become irritated and swollen, causing a sore throat that's especially painful when swallowing. Your child may get white or yellow spots, or a coating on the throat and tonsils, and the lymph nodes in the neck may swell and become tender to touch.

Strep throat is most common among 5- to 10-year-olds. Up to 20% of schoolchildren may be carrying the bacteria but show no symptoms, though they can still spread the infection. In kids, strep throat may cause body aches, headaches, stomachaches, nausea, vomiting, or listlessness. The infection usually doesn't include other cold symptoms (such as sneezing, coughing, or a runny or stuffy nose).
Most sore throats in kids are caused by viral infections, which clear up on their own without antibiotic treatment. While strep throat sometimes can go away within a few days without treatment, doctors prescribe antibiotics to prevent related complications that can be serious, such as rheumatic fever.
Why It's Done
The rapid strep test is done to help quickly see whether a child's sore throat is caused by a strep infection vs. other germs (usually viruses) that don't require antibiotic treatment.
A doctor may do a rapid strep test done if a child:
- has symptoms of a strep throat infection and doesn't have symptoms typical of a virus infection
- has a sore throat and has been exposed to someone known to have a strep throat, or if there are many strep throat cases in the community
Sometimes, doctors do a throat culture instead of a rapid strep test. A throat culture is more accurate than a rapid strep test, but the results take longer (2-3 days) to come back.