The modified Centor (McIsaac) score helps avoid unnecessary antibiotics for sore throats, most of which are viral. Scores of 0–1 need no testing; 2–3 call for a rapid strep test or culture; 4 or more may justify testing and treatment.
How to use the Centor Score Calculator
- Temperature above 38 °C (100.4 °F)
- Tonsillar swelling or exudate
- Tender, swollen anterior cervical lymph nodes
- Absence of cough
- Age
Results update as you type, and every field accepts the units shown in its menu.
How it works
Each answer carries the points shown in the published score. The calculator adds them up and maps the total to the published interpretation.
Scoring table
| Item | Answers and points |
|---|---|
| Temperature above 38 °C (100.4 °F) | No = 0; Yes = 1 |
| Tonsillar swelling or exudate | No = 0; Yes = 1 |
| Tender, swollen anterior cervical lymph nodes | No = 0; Yes = 1 |
| Absence of cough | No = 0; Yes = 1 |
| Age | 3–14 years = 1; 15–44 years = 0; 45 years or older = -1 |
Inputs explained
| Field | What to enter |
|---|---|
| Temperature above 38 °C (100.4 °F) | Choose one: No, Yes |
| Tonsillar swelling or exudate | Choose one: No, Yes |
| Tender, swollen anterior cervical lymph nodes | Choose one: No, Yes |
| Absence of cough | Choose one: No, Yes |
| Age | Choose one: 3–14 years, 15–44 years, 45 years or older |
Health note: this calculator is for education and screening only and is not a diagnosis or treatment advice. Discuss your results with a qualified clinician.
Formula
Score = sum of the points for each item
Worked example
Inputs — Temperature above 38 °C (100.4 °F): Yes; Tonsillar swelling or exudate: Yes; Tender, swollen anterior cervical lymph nodes: No; Absence of cough: Yes; Age: 15–44 years.
Results — Modified Centor score = 3; Probability of strep and action = 28–35% – rapid strep test.
Key terms
- GAS
- Group A Streptococcus.
Frequently asked questions
What score needs a strep test?
2 or more, in most guidelines.
Why not give antibiotics to everyone?
Most sore throats are viral; unnecessary antibiotics cause side effects and resistance.
What is FeverPAIN?
A UK alternative score using fever, purulence, attend rapidly, inflamed tonsils and no cough.