Centor Score Calculator (Modified/McIsaac)

In 1981, Dr. Robert Centor, with associates, published an article in Medical Decision Making. Its goal was to see if clinical findings could stratify the probability that an adult patient with a sore throat had group A Streptococcus.

They analyzed 234 patients who filled out their questionnaire and had throat cultures performed. They noticed that the set of four variables could decently predict the positive culture. Almost two decades later, Dr. Warren McIsaac modified the scale by adding the fifth variable – age.

The Centor (Modified/McIsaac) criteria is a kind of strep throat criteria and consists of four variables:

• Fever >38 °C / 100.4 °F;
• Tonsillar exudates;
• Tender anterior cervical lymphadenopathy; and
• Absence of a cough.

Each of them may give you 1 point. The fifth variable — age — may give you -1, 0, or +1 points.

Use the temperature conversion tool to convert between Celsius and Fahrenheit.

The greater the Centor score, the bigger the probability of streptococcal infection causing pharyngitis.

The interpretation of the Centor score should be as follows:

• 0-1 point: no further testing or antibiotics are required.

• 2-3 points: culture test should be taken; antibiotics only needed with positive culture results.

• 4-5 points: treat empirically with antibiotics.

A 24-year-old male student came to the doctor due to a sore throat, which started on the day before the visit. The patient also reports productive cough, sneezing, and a runny nose. His body temperature is 37.8 Celcius. He denies pain in the neck. On medical examination, there are enlarged, swollen tonsils with exudate. However, there is no lymphadenopathy.

To assess appropriate patient management concerning possible bacterial etiology of pharyngitis, a doctor should calculate the Centor score. The patient receives: body temperature — 0 points, tonsils — 1 point, lymph nodes — 0 points, cough — 0 points, and age — 0 points. Altogether — 1 point. In this case, no antibiotic or throat culture is necessary, as the risk of streptococcal infection is 5%-7%.

You might also be interested in our sepsis calculator or the amoxicillin pediatric dosage calculator.

❗ Warning!
Using any calculator may never replace a medical examination. If you feel any symptoms, contact your physician!