Diagnosis of Strep Throat

Strep throat diagnosis involves taking a history of symptoms and performing a physical examination and strep tests. During physical exam, the physician looks at the throat and tonsils for signs of inflammation or infection and feels the neck for swollen lymph glands.

A rapid strep test often is performed in the office. In this test, a cotton swab is used to take a sample of the fluids from the back of the throat and the sample is examined for strep bacteria.

Results of rapid strep tests are available in about 15 minutes. If the results are positive, the diagnosis of strep is confirmed and antibiotics are prescribed.

Negative test results from the rapid strep test are not reliable—the test has a false-negative rate of approximately 20%. If the test is negative, physicians often take another throat swab and send it to a laboratory for further testing just to be sure. The results of this test are available in 24–48 hours. In most cases, the physician will contact you with the results. If you don't hear from the doctor by the second day, be sure to call the office.

Publication Review By: Stanley J. Swierzewski, III, M.D.

Published: 28 Aug 2008

Last Modified: 03 Jun 2011