Centor Score Calculator

The Centor Score Calculator estimates the probability of Group A Streptococcal Pharyngitis based on clinical criteria like fever, absence of cough, and tonsillar exudates. This tool helps clinicians quickly assess infection risk to make informed treatment decisions. Whether evaluating a child with a sore throat or an adult with swollen lymph nodes, this calculator streamlines the diagnostic process.

Enter the patient's age in years
Has the patient had a fever (≥38°C or 100.4°F)?
Is cough absent from the patient's symptoms?
Are there white patches or pus on the tonsils?
Are the lymph nodes in the front of the neck tender or swollen?

Important: This tool is for screening only and does not replace a clinical exam. It is recommended to always consider local prevalence rates. This calculator is for informational purposes and not a substitute for professional medical advice, screening assessment, or treatment.

How Probability of Strep Throat Is Calculated

The Modified Centor Score predicts the likelihood of a bacterial throat infection by evaluating five specific clinical findings. This method helps doctors distinguish between viral and bacterial causes to ensure proper care.

Centor Score = Age Score + Fever + Absence of Cough + Tonsillar Exudates + Tender Lymph Nodes

Where:

  • Age Score: 1 point (ages 3-14), 0 points (ages 15-44), -1 point (ages 45+)
  • Other Criteria: 1 point if present, 0 points if absent

Points are assigned based on age, fever history, absence of cough, swollen lymph nodes, and tonsillar exudates. Higher totals indicate a greater chance of Strep throat. By standardizing these observations, the score provides an evidence-based estimate that guides diagnostic testing and treatment decisions effectively.

What Your Probability of Strep Throat Means

Understanding your probability helps determine the best course of action for patient care. A low score (0-1) typically suggests a viral infection, meaning antibiotics are usually unnecessary and testing is not required. A moderate score (2-3) indicates a significant risk where a rapid strep test or throat culture is the best next step to confirm the screening assessment before prescribing medication. A high score (4-5) suggests a 50% or greater likelihood of Strep throat, often warranting empiric antibiotic treatment or immediate further testing.

Monitor symptoms closely and adjust care if the condition worsens or new symptoms appear.

Calculation logic verified using publicly available standards.

View our Accuracy & Reliability Framework →