History and clinical examination can be used to diagnosis viral pharyngitis when clear viral symptoms (e.g., cough, rhinorrhea, hoarseness, oral ulcers, conjunctivitis) are present; these patients do not need testing for group A strep. However, clinical examination cannot be used to differentiate viral and group A strep pharyngitis in the absence of viral symptoms, even for experienced clinicians. Group A streptococcal pharyngitis may be diagnosed with the help of rapid antigen detection test (RADT) and throat culture.^[1]

History and clinical examination can be used to diagnosis viral pharyngitis when clear viral symptoms (e.g., cough, rhinorrhea, hoarseness, oral ulcers, conjunctivitis) are present; these patients do not need testing for group A strep. However, clinical examination cannot be used to differentiate viral and group A strep pharyngitis in the absence of viral symptoms, even for experienced clinicians. Group A streptococcal pharyngitis may be diagnosed with the help of following laboratory tests:^[1]

RADTs have higher specificity for group A streptococcal throat but lower sensitivity than throat culture.^{[2][3][4][5][6]}

Throat culture is the gold standard diagnostic test for group A streptococcal pharyngitis. Individuals with negative rapid antigen detection test and high clinical suspicion of strep throat must be confirmed with throat culture.^{[3][4][5][6][7]}

There is no role of group A streptococcal serology in the diagnosis of strep throat.

Molecular assays such as nucleic acid amplification tests (NAAT) and polymerase chain reaction assays (PCR) are not routinely used for the detection of strep throat.