Centor / McIsaac Score

Strep pharyngitis — pretest probability

Tonsillar swelling or exudate

Tender or swollen anterior cervical nodes

History of fever > 38 °C

Absence of cough

Age (McIsaac modifier)

3–14 years (+1)

15–44 years (0)

45 years or older (−1)

Evidence

Original publication

Centor RM, Witherspoon JM, Dalton HP, Brody CE, Link K. The diagnosis of strep throat in adults in the emergency room. Original 4-criterion score (exudate, tender anterior cervical nodes, history of fever, absence of cough).

Medical Decision Making, 1981

Open source

Validation

McIsaac WJ, White D, Tannenbaum D, Low DE. A clinical score to reduce unnecessary antibiotic use in patients with sore throat. Added the age modifier (+1 for 3–14 years, −1 for ≥ 45) used here.

Canadian Medical Association Journal, 1998

Open source

Last reviewed: 2026-09

Report an error in this calculator

MedScore is an educational and clinical decision-support tool. It does not provide a diagnosis, a treatment, or a drug-dosing recommendation, and it does not replace clinical judgement or local guidelines. Confirm every result against the original source before acting on it. The treating clinician remains responsible for all decisions.