From the Guidelines
The Centor criteria are a clinical prediction rule used to assess the likelihood of group A beta-hemolytic streptococcal (GABHS) pharyngitis in patients presenting with sore throat, and include four components: presence of tonsillar exudates, tender anterior cervical lymphadenopathy, absence of cough, and history of fever (temperature >38°C). The criteria are used to determine the likelihood of a bacterial infection, with a score ranging from 0 to 4 [ 1 ]. A score of 0-1 suggests a low risk of strep throat (less than 10%), and antibiotics are not recommended [ 1 ].
Key Components of the Centor Criteria
- Presence of tonsillar exudates
- Tender anterior cervical lymphadenopathy
- Absence of cough
- History of fever (temperature >38°C)
Interpretation of Centor Score
- A score of 0-1: low risk of strep throat, antibiotics not recommended
- A score of 2-3: moderate risk, rapid antigen testing or throat culture should be considered before prescribing antibiotics
- A score of 4: high risk, empiric antibiotic therapy with penicillin V or amoxicillin may be appropriate [ 1 ]
Antibiotic Treatment
Penicillin V (500 mg orally twice daily for 10 days) or amoxicillin (500 mg orally three times daily for 10 days) are recommended as first-line antibiotic treatments [ 1 ]. For penicillin-allergic patients, alternatives include clindamycin or a macrolide like azithromycin. The Centor criteria help clinicians make more judicious decisions about antibiotic use, reducing unnecessary prescriptions while identifying patients who would benefit from treatment, thereby preventing complications like rheumatic fever and peritonsillar abscess [ 1 ].
From the Research
Centor Criteria
The Centor criteria are a set of clinical criteria used to predict the risk of Group A beta-hemolytic streptococcal (GABHS) pharyngitis. The criteria include:
- Tonsillar exudates
- Tender anterior cervical adenopathy
- Fever
- Absence of cough
Modified Centor Score
The modified Centor score is a clinical scoring system that assigns points for each of the Centor criteria present. The score is used to predict the risk of GABHS pharyngitis and guide diagnostic testing and treatment decisions 2, 3, 4.
- A score of 0-1 indicates a low risk of GABHS pharyngitis
- A score of 2-3 indicates a moderate risk of GABHS pharyngitis
- A score of 4 indicates a high risk of GABHS pharyngitis
Diagnostic Accuracy
Studies have evaluated the diagnostic accuracy of the Centor score in diagnosing GABHS pharyngitis. One study found that a Centor score of 3 or 4 had a sensitivity of 50% and specificities of 97.6% and 100%, respectively, for diagnosing GABHS pharyngitis 5.
Clinical Decision Rules
Clinical decision rules, such as the modified Centor score, are recommended to assess the risk of GABHS infection, followed by rapid antigen testing if a diagnosis is unclear, before prescribing antibiotics 6.
Key Points
Key points to consider when using the Centor criteria include:
- The presence of cough, coryza, and diarrhea suggests a viral etiology rather than GABHS pharyngitis 2, 4
- The modified Centor score can be used to guide diagnostic testing and treatment decisions 2, 3, 4
- Rapid antigen detection tests and throat cultures can be used to confirm the diagnosis of GABHS pharyngitis 2, 3, 6, 4