In many cases, doctors use a simple test to detect streptococcal bacteria, the cause of strep throat. The doctor rubs a sterile swab over the back of the throat to get a sample of secretions and sends the sample to a lab for testing. Many clinics are equipped with a lab that can get a test result for a rapid antigen test within a few minutes. However, a second, often more reliable test, called a throat culture, is sometimes sent to a lab that returns results within 24 to 48 hours.

Rapid antigen tests aren't as sensitive, although they can detect strep bacteria quickly. Because of this, the doctor may send a throat culture to a lab to test for strep throat if the antigen test comes back negative.

In some cases, doctors may use a molecular test to detect streptococcal bacteria. In this test, a doctor swipes a sterile swab over the back of the throat to get a sample of secretions. The sample is tested in a lab. Your or your child's doctor may have accurate results within a few minutes.