Centor Score for Diagnosing Group A Streptococcal Pharyngitis

Clinical Criteria and Scoring

The Centor score is a validated clinical decision tool that stratifies the probability of group A streptococcal (GAS) pharyngitis in adults with sore throat, using four clinical criteria to guide testing and treatment decisions, including fever by history, tonsillar exudates, tender anterior cervical lymphadenopathy, and absence of cough, with each criterion receiving one point for a maximum score of 4 1, 2
The four components of the Centor score are: fever by history (1 point), tonsillar exudates (1 point), tender anterior cervical lymphadenopathy (1 point), and absence of cough (1 point) 1

The score directly correlates with probability of streptococcal infection, with scores ranging from 0 to 4 and corresponding probabilities of 1-2.5%, 5-10%, 11-17%, 28-35%, and 51-53% for scores 0, 1, 2, 3, and 4, respectively 1, 2
The American Academy of Family Physicians recommends using the Centor score to guide testing and treatment decisions for adults with sore throat, with scores 0-2 indicating a low probability of GAS pharyngitis and scores 3-4 indicating a higher probability 1, 2

For scores 0-2, the American College of Physicians recommends against testing or treating with antibiotics, and instead providing symptomatic management with ibuprofen or acetaminophen 1, 3
For scores 3-4, the Infectious Diseases Society of America recommends performing a rapid antigen detection test (RADT) and treating with penicillin V for 10 days if the test is positive 1, 3

The Centor score was validated only in adults, not children, and the modified McIsaac score adds age stratification for broader applicability 1, 2
Even with a score of 4, only about half of patients actually have GAS pharyngitis, highlighting the need for confirmatory testing rather than empiric treatment 2

Both the posterior pharyngeal wall and both tonsils must be swabbed to optimize test accuracy, and improper technique can reduce sensitivity and lead to false-negative results 1, 2

When antibiotics are indicated, the benefits are modest, with symptom reduction of only 1-2 days, and the risks of side effects, antibiotic resistance, and costs must be weighed against the benefits 1, 3
Penicillin V remains the first-line treatment for GAS pharyngitis when antibiotics are warranted, according to the American Academy of Pediatrics 1, 3