What It Is
A throat culture or strep test is performed by using a throat swab to detect the
presence of group A streptococcus bacteria, the most common cause of strep
throat. These bacteria also can cause other infections, including scarlet fever, abscesses,
and pneumonia.
A sample swabbed from the back of the throat is put on a special plate (culture)
that enables bacteria to grow in the lab. The specific type of infection is determined
using chemical tests. If bacteria don't grow, the culture is negative and the person
doesn't have a strep throat infection.
Strep throat is a bacterial infection that affects the back of the throat and the
tonsils, which become irritated and swell, causing a sore throat that's especially
painful when swallowing. White or yellow spots or a coating on the throat and tonsils
also might be present, and the lymph nodes along the sides of the neck may swell.

Strep throat is most common among school-age children. The infection may cause
headaches, stomachaches, nausea, vomiting, and listlessness. Strep throat infections
don't usually include cold symptoms (such as sneezing, coughing, or a runny or stuffy
nose).
While symptoms of strep throat can go away within a few days without direct treatment,
doctors will prescribe antibiotics to help prevent related complications that can
be serious, such as rheumatic fever. Taking antibiotics reduces the length of time
a person is contagious.
Why It's Done
The throat culture test can help find the cause of a sore throat. Often, a sore
throat is caused by a virus, but a throat culture will see if it's definitely caused
by strep bacteria, helping doctors decide on the proper treatment.
Preparation
Encourage your child to stay still during the procedure. Be sure to tell the doctor
if your child has taken any antibiotics recently, and try to have your child avoid
antiseptic mouthwash before the test as this could affect test results.