The purpose of this study is to determine if the rapid antigen detection test for Group A streptococcal pharyngitis diagnosis might yield higher rates of false positive results in patients who have been treated for GAS pharyngitis within 28 days of the test.

Strep pharyngitis, or strep throat, is a common infection afflicting children, aged 2 and above. Testing for strep pharyngitis consists of a rapid test and/or a throat culture. However, it has been observed that rapid testing may not be accurate in children with a recent history of strep pharyngitis. Therefore, this study aims to determine the accuracy of rapid strep testing in children who are presenting with symptoms of strep throat, who also have a recent history of and treatment for strep pharyngitis. By demonstrating an inaccuracy in rapid strep testing in patients with a recent history of strep pharyngitis, unnecessary testing and antibiotic use may be decreased, thereby reducing costs, overuse of antibiotics, and antibiotic resistance.

The participants in the study will include 600 children, aged 2 to 20 years old, selected from a private practice in Northern Virginia who present to the practice with signs or symptoms suggestive of acute pharyngitis. Subjects are children who are presenting with signs and symptoms suggestive of acute pharyngitis by the Centor criteria, including sore throat, fever, abdominal pain and cervical lymphadenitis. Any child with above presenting symptoms who is to undergo Streptococcus rapid antigen testing will be recruited to participate in the study.

A letter of consent will be provided to the parents and guardians of the involved child, stating that the study will be voluntary and confidential, and that all results will be kept in a safe environment.

Investigators will be testing the difference between two proportions, the false positive rate in previously treated compared to those not treated.

Inclusion Criteria:

• 2-20 years old
• Current signs and symptoms suggestive of acute pharyngitis, including sore throat, fever, abdominal pain and cervical lymphadenitis.

Exclusion Criteria:

• Potential subjects who have been treated with less than 10 days of antibiotic therapy
• Patients who report non-compliance with previous antibiotic therapy
• Patients who have already been included in the study and children with evidence of GAS carrier status

The participants in the study will include 600 children, aged 2 to 20 years old, selected from a private practice in Northern Virginia who present to the practice with signs or symptoms suggestive of acute pharyngitis.

Potential subjects who have been treated with less than 10 days of antibiotic therapy, patients who report non-compliance with previous antibiotic therapy, patients who have already been included in the study and children with evidence of GAS carrier status will be excluded.