A throat culture is a test to see if a bacterial infection is present in the throat.
This procedure is usually ordered on a person who has symptoms of a sore throat, with or without fever.
Most often, the primary purpose of the culture is to distinguish strep throat due to Group A strep, which has a specific curative treatment, from other causes of sore throat that can only be treated to relieve symptoms.
A tongue depressor is used to hold the tongue down. A special swab is inserted into the mouth and brushed against the throat and tonsils. The swab is then sent to a laboratory to see if there are any bacteria. Some healthcare professionals' offices are able to do this analysis on site.
Nelson Textbook of Pediatrics, 1996, Behrman et al.