Calc Function

    • Calcs that help predict probability of a diseaseDiagnosis
    • Subcategory of 'Diagnosis' designed to be very sensitiveRule Out
    • Disease is diagnosed: prognosticate to guide treatmentPrognosis
    • Numerical inputs and outputsFormula
    • Med treatment and moreTreatment
    • Suggested protocolsAlgorithm





    Chief Complaint


    Organ System


    Patent Pending

    Centor Score (Modified/McIsaac) for Strep Pharyngitis

    Estimates probability that pharyngitis is streptococcal, and suggests management course.


    Use only in patients with recent onset (≤3 days) acute pharyngitis.

    When to Use
    Why Use

    Children with pharyngitis, primarily; the risk of GAS decreases significantly with age into adulthood.

    • The Centor Score correlates directly with risk of positive throat culture for GAS (Group A Streptococcus).
    • New 2012 guidelines from the IDSA (Infectious Disease Society of America) no longer recommend empiric treatment for patients alone; they recommend testing patients that are at higher risk for strep pharyngitis, but not giving antibiotics until a rapid test is positive or a throat culture is positive.
    • The modified criteria by McIsaac et al include an age component, along with tonsillar swelling, as part of the rule. GAS is incredibly rare in patients under 3 and less common in older adults, so this can help clinicians risk stratify patients.
    • Most cases of pharyngitis are viral in origin, and with the rare incidence of rheumatic fever, along with the questionable benefits of early antibiotics to prevent sequelae like peritonsillar abscess, antibiotics are prescribed much less often. Steroids (like dexamethasone) and NSAIDS often provide similar pain relief and resolution of symptoms to antibiotics.
    • Most pharyngitis is viral and does not respond to antibiotic treatment. The Centor Score attempts to predict which patients will have culture-confirmed streptococcal infections of their pharynx to help determine which patients to test in the first place.
    • The newer FeverPAIN Score is similar, but the Centor Score has the distinguishes between adolescents and young adults from pre-adolescents—important because strep carrier rates are higher in preadolescents than adolescents/young adults, and older patients are more likely to have severe symptoms and develop suppurative complications (Mitchell 2011).
    3-14 years
    15-44 years
    ≥45 years
    Cough present
    Cough absent


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    Next Steps
    Creator Insights


    Steroids and NSAIDS improve symptoms; antibiotics are often indicated in streptococcal pharyngitis, but do not prevent its suppurative complications, like peritonsillar abscess.

    Critical Actions

    • Carefully consider patients with symptom duration longer than 3 days, even though the Centor Score does not apply.
    • While symptoms are not compatible with a diagnosis of acute pharyngitis, these patients require evaluation for suppurative complications (peritonsillar abscess or Lemierre syndrome), or viral infections in adult patients (infectious mononucleosis or acute HIV) (Centor 2017).
    About the Creator
    Dr. Robert M. Centor
    Are you Dr. Robert M. Centor?
    Dr. Warren McIsaac
    Are you Dr. Warren McIsaac?