Centor / McIsaac Strep Score
Medical context
Estimate group A strep pharyngitis probability with the modified Centor (McIsaac) score.
Emergency clinicians use this at triage, resuscitation, and disposition to standardize risk communication across shifts.
This page explains the Centor formula, how to interpret the output, known limitations, and peer-reviewed references so you can verify results against primary sources and local protocols.
It is grouped under Emergency Medicine because trauma, triage, and acute risk scores used in the ed.
How to use this calculator
- Enter the values requested by the Centor calculator using the units shown beside each field.
- Review the calculated result and read the interpretation section before acting on the output.
- Check limitations and references if the result will change management, dosing, or disposition.
- Use the related calculators section when you need supporting values (for example electrolytes, weight, or complementary risk scores).
Calculator
Result
1
Low risk — no testing/antibiotics typically
Educational use only. Confirm results with clinical judgment, primary sources, and local protocols. Not a substitute for professional medical advice. Full disclaimer.
Formula
Exudate, nodes, fever, absent cough (+1 each) plus age modifier.
Interpretation
Low scores often need no test/antibiotics; mid scores suggest testing; high scores may warrant treatment pathways.
Limitations
Viral syndromes overlap; follow local antibiotic stewardship guidance.
Frequently asked questions
- Why does absent cough add a point?
- Cough suggests viral illness; its absence raises GAS likelihood.
- Is the Centor result enough to make a treatment decision?
- No. Calculators support medical decision-making but do not replace examination, shared decision-making, institutional protocols, or consultant input when stakes are high.
- Does Calcmedical store the values I type in?
- Inputs are processed in your browser for this session. We do not ask for patient names or medical record numbers. See our privacy policy for hosting and analytics details.
References
- Centor RM et al.
- McIsaac WJ et al. modified Centor