Calculate the Centor or McIsaac score for streptococcal pharyngitis likelihood.
Even the highest score corresponds to only about a 55 per cent probability of streptococcal infection, which is why the score guides testing rather than replacing it. Most sore throats are viral regardless of score. The score exists primarily to reduce unnecessary antibiotic prescribing, since the majority of sore throats resolve without treatment.
Centor Score
Centor sums four clinical criteria; McIsaac adds an age modifier of plus or minus one
This reproduces a published formula for educational and reference use only. It is not a diagnostic tool, does not account for individual clinical context, and must not be used to make or change treatment decisions. Clinical assessment by a qualified healthcare professional is always required. Antibiotic decisions must be made by a prescriber following local guidance and resistance patterns. Seek urgent care for difficulty swallowing or breathing, drooling, or a severe unilateral sore throat.
Centor sums four clinical criteria; McIsaac adds an age modifier of plus or minus one Even the highest score corresponds to only about a 55 per cent probability of streptococcal infection, which is why the score guides testing rather than replacing it. Most sore throats are viral regardless of score.
The score exists primarily to reduce unnecessary antibiotic prescribing, since the majority of sore throats resolve without treatment.
This calculator takes 5 inputs: Tonsillar exudate, Tender anterior cervical nodes, History of fever above 38 Celsius, Cough absent, Age. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.