Centor Score (McIsaac Modification) for Streptococcal Pharyngitis
Who needs a throat swab, and the point where India's RHD burden changes the calculus · v1.01. Age
2. Clinical Findings (Centor Criteria)
Clinical Application & Nuances
1. What the Score Was Built to Do
Centor's four findings were derived in adults presenting to an emergency room, to estimate the probability of streptococcal pharyngitis from examination alone. McIsaac added the age adjustment in 1998 so the same criteria would work in children, in whom group A streptococcus is more common, and in older adults, in whom it is less so. The goal in both papers was the same: fewer unnecessary antibiotics for a sore throat that is very unlikely to be streptococcal.
2. A Point to Note for India
3. A Validation Study From Chennai
A 2019 study of 120 children in Chennai found the modified Centor score performed poorly as a standalone predictor of culture-confirmed streptococcal pharyngitis in that population (area under the curve 0.589), and documented significant antibiotic resistance among the beta-haemolytic streptococci isolated. This is one Indian paediatric cohort, not a national figure, and it argues for treating the score as one input to the decision to test rather than a substitute for testing.
4. Negative Predictive Value Is the Score's Real Strength
A score of 0 or 1 carries a low probability of group A streptococcus in the populations the score was derived in, and this is the range in which withholding both testing and antibiotics is best supported. The higher bands are better read as "worth testing" than as "treat empirically", because a rapid antigen test or culture remains more accurate than the score itself at any point value.
Algorithm References & Evidence Base
- Centor RM, Witherspoon JM, Dalton HP, Brody CE, Link K. The diagnosis of strep throat in adults in the emergency room. Med Decis Making. 1981;1(3):239-246.
- McIsaac WJ, White D, Tannenbaum D, Low DE. A clinical score to reduce unnecessary antibiotic use in patients with sore throat. CMAJ. 1998;158(1):75-83.
- McIsaac WJ, Kellner JD, Aufricht P, Vanjaka A, Low DE. Empirical validation of guidelines for the management of pharyngitis in children and adults. JAMA. 2004;291(13):1587-1595.
- Shulman ST, Bisno AL, Clegg HW, et al. Clinical practice guideline for the diagnosis and management of group A streptococcal pharyngitis: 2012 update by the Infectious Diseases Society of America. Clin Infect Dis. 2012;55(10):e86-e102.
- World Health Organization. WHO Guideline on the Prevention and Diagnosis of Rheumatic Fever and Rheumatic Heart Disease. Geneva: WHO; 2024.
- Saxena A, Kaur K. Rheumatic fever and rheumatic heart disease in Indian children: setting priorities in the current decade. Indian Heart J. 2024.
- Vasudevan J, Mannu A, Ganavi G. McIsaac Modification of Centor Score in Diagnosis of Streptococcal Pharyngitis and Antibiotic Sensitivity Pattern of Beta-hemolytic Streptococci in Chennai, India. Indian Pediatr. 2019;56(1):49-52.
- Fine AM, Nizet V, Mandl KD. Large-scale validation of the Centor and McIsaac scores to predict group A streptococcal pharyngitis. Arch Intern Med. 2012;172(11):847-852.
How to Cite This Tool
AMA Style:
Umakanth S. Centor / McIsaac Score for Streptococcal Pharyngitis. MEDiscuss. Published 2026. Accessed .
Vancouver Style:
Umakanth S. Centor / McIsaac Score for Streptococcal Pharyngitis [Internet]. MEDiscuss.org; 2026 [cited ]. Available from:
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