Streptococcus pyogenes Ag

Group A Streptococcus , also known as group A strep, is a type of bacteria that often lives in the nose and throat. It causes strep throat and other infections. Strep throat is an infection that affects the throat and tonsils. You can get strep throat at any age, but it's most common in children ages 5 to 15 years old.

A strep A test is most often used to find out if a sore throat and other symptoms are being caused by strep throat or by a viral infection. Strep throat needs to be treated with antibiotics to prevent complications. But most sore throats are caused by viruses, and antibiotics don't work on viral infections.