Pharyngitis diagnostic study of choice

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Delband Yekta Moazami, M.D.[2]


Diagnostic tests provided include throat culture and checking for rapid antigen detection(RADT). Although the sensitivity and specificity of rapid antigen detection testing have improved dramatically, a throat culture is considered the diagnostic standard. It is possible to use the adjusted Centor score to help doctors determine which patients do not need testing, throat culture, rapid antigen detection testing, or empirical antibiotic therapy.

Diagnostic Study of Choice

Study of choice

The diagnostic study of choice for bacterial pharyngitis is the throat culture. A single-swab throat culture is 90 to 95 percent sensitive with proper sampling and plating techniques.[1][2]

The comparison of various diagnostic studies for bacterial pharyngitis

Test Sensitivity Specificity
Throat culture 90% to 95% 97% to 100%
RADT 38% to 100% 54% to 100%

Even though the results of RADT are immediate, the sensitivity and specificity of the results vary widely. each kit is pathogen-specific and unable to distinguish widely Between Bacterial and Viral Pharyngitis. Thus, negative results cannot rule out non-GAS bacterial pharyngitis

Sequence of Diagnostic Studies

The original Center score uses four signs and symptoms to estimate the probability of acute streptococcal pharyngitis in adults with a sore throat The score was later modified by adding age. It is important to evaluate for a definitive diagnosis to exclude GAS and to avoid unnecessary lab tests and antibiotic use. Centor criteria are a widely used and accepted clinical decision tool in identifying patients for whom neither microbiologic tests nor antimicrobial therapy is necessary. The Center score to use for children and adults with a sore throat to estimate the probability of Streptococcus pyogenes infection.[2] The various investigations must be performed in the following order:

Name of Diagnostic Criteria

Centor criteria

Modified Centor criteria Appropriate management according to the total score
Criteria Points Total score Chance of streptococcal infection in community

with usual levels of infection, %

Suggested management
Fever (temperature > 38°C) +1 0 2-3% No culture or antibiotic is required
Absence of cough +1 1 4-6%
Swollen and tender anterior cervical nodes +1 2 10-12% RADT or Culture and treat only if culture result is positive
Tonsillar swelling or exudates +1 3 27-28%
Age 3–14 yr +1 4 38–63% Culture all and treat emperically with penicillin on clinical grounds
Age 15–44 yr 0
Age ≥ 45 yr -1


  1. Sykes EA, Wu V, Beyea MM, Simpson M, Beyea JA (April 2020). "Pharyngitis: Approach to diagnosis and treatment". Can Fam Physician. 66 (4): 251–257. Vancouver style error: initials (help)
  2. 2.0 2.1 Vazquez MN, Sanders JE (December 2017). "Diagnosis and management of group A streptococcal pharyngitis and associated complications". Pediatr Emerg Med Pract. 14 (12): 1–20. PMID 29185672.

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