🦠 Centor Score (Modified / McIsaac)
Estimate the likelihood of strep throat with the modified Centor (McIsaac) score.
Clinical takeaway
Confirm with rapid antigen test/culture before antibiotics in most settings.
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When to use
Decide on testing/treatment in sore throat.
How it works
1 point each: tonsillar exudate, tender anterior nodes, fever > 38°C, absence of cough; age 3–14 +1, 15–44 0, ≥ 45 −1.
Key points
- Confirm with rapid antigen test/culture before antibiotics in most settings.
- Low scores: no testing or antibiotics.
- The McIsaac modification adds the age adjustment.
References
Decision support for licensed clinicians only; not a substitute for clinical judgement, diagnosis or local protocols.
Worked calculation
The values below come from this tool's own example placeholders and are computed server-side with the formula shown on this page, so the arithmetic can be checked quickly. It demonstrates how to substitute values only — it is not clinical advice and not a real case.
| Tonsillar exudate/swelling | No |
|---|---|
| Tender anterior cervical nodes | No |
| Fever > 38°C | No |
| Cough absent | No (cough present) |
| Age | 3–14 (+1) |
→Centor (McIsaac)1
- Strep probability：~5–10%
- Guidance：Most guidelines recommend confirming with rapid antigen test/culture before antibiotics rather than treating on score alone.
| Tonsillar exudate/swelling | Yes (+1) |
|---|---|
| Tender anterior cervical nodes | Yes (+1) |
| Fever > 38°C | Yes (+1) |
| Cough absent | Yes (+1) |
| Age | ≥ 45 (−1) |
→Centor (McIsaac)3
- Strep probability：~28–35% — test
- Guidance：Most guidelines recommend confirming with rapid antigen test/culture before antibiotics rather than treating on score alone.
Frequently asked questions
- What is Centor Score (Modified / McIsaac)?
- Estimate the likelihood of strep throat with the modified Centor (McIsaac) score.
- How is Centor Score (Modified / McIsaac) calculated? What is the core formula?
- 1 point each: tonsillar exudate, tender anterior nodes, fever > 38°C, absence of cough; age 3–14 +1, 15–44 0, ≥ 45 −1.
- When is Centor Score (Modified / McIsaac) used?
- Decide on testing/treatment in sore throat.
- What are the key clinical points for Centor Score (Modified / McIsaac)?
- Confirm with rapid antigen test/culture before antibiotics in most settings. Low scores: no testing or antibiotics. The McIsaac modification adds the age adjustment.
- What are the limits and cautions when using Centor Score (Modified / McIsaac)?
- For licensed clinicians and clinical researchers. Interpret results with history, investigations and local protocols; not a diagnosis or prescription, and not a substitute for multidisciplinary decision-making or local guidelines.
- How is Centor Score (Modified / McIsaac) calculated in practice? Can you show a worked example?
- Inputs: Tonsillar exudate/swelling No, Tender anterior cervical nodes No, Fever > 38°C No, Cough absent No (cough present), Age 3–14 (+1) → Result: Centor (McIsaac) 1（Strep probability: ~5–10%, Guidance: Most guidelines recommend confirming with rapid antigen test/culture before antibiotics rather than treating on score alone.） Inputs: Tonsillar exudate/swelling Yes (+1), Tender anterior cervical nodes Yes (+1), Fever > 38°C Yes (+1), Cough absent Yes (+1), Age ≥ 45 (−1) → Result: Centor (McIsaac) 3（Strep probability: ~28–35% — test, Guidance: Most guidelines recommend confirming with rapid antigen test/culture before antibiotics rather than treating on score alone.）