Centor Score Calculator - Modified McIsaac Criteria

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Age is part of the McIsaac modification. Children aged 3-14 score +1; adults 45+ score -1. GAS pharyngitis is rare under age 3.
Pus on the tonsils or marked tonsillar enlargement visible on examination.
Anterior cervical lymphadenopathy - tender or swollen lymph nodes along the front of the neck.
A measured temperature above 38 degrees C (100.4 degrees F) or a history of fever.
Absence of cough is a positive predictor for GAS. If the patient has a cough, this criterion is not met.
Centor ScoreLow Risk
0

Modified Centor (McIsaac) total score

GAS Probability1-3%
Recommended ActionNo testing or antibiotics needed.
Age Points0
Criteria Points0
0 points
Low Risk<2Moderate Risk2-4High Risk4+

Score 0: Low probability of GAS pharyngitis (1-3%).

  • With a score of 0, GAS pharyngitis probability is approximately 1-3%. Testing and antibiotics are generally not recommended.
  • Supportive care (rest, fluids, analgesics) is the standard approach for low-risk pharyngitis.
  • The Modified Centor Score does not replace clinical judgment - use it alongside the full clinical picture.

Next stepProvide symptomatic relief: analgesics such as ibuprofen or acetaminophen, throat lozenges, and adequate hydration. Return if symptoms worsen.

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