What is the Centor Score?

The Centor Score (modified by McIsaac) estimates the probability that a sore throat is caused by Group A Streptococcus. It uses 5 criteria: tonsillar exudates, tender anterior cervical lymphadenopathy, fever over 38°C, absence of cough, and patient age. Scores range from -1 to 5. A score of 0-1 suggests a low probability of strep (less than 10%), while a score of 4-5 suggests a probability of about 50%.

When should I prescribe antibiotics for a sore throat?

Australian Therapeutic Guidelines recommend against routine antibiotics for sore throat. Most sore throats are viral. For patients with a high Centor Score (4-5), consider a rapid strep test or throat culture before prescribing. Antibiotics (phenoxymethylpenicillin 500mg BD for 10 days) are recommended for confirmed Group A Strep, Aboriginal and Torres Strait Islander patients at risk of rheumatic fever, or patients who are systemically unwell.

Centor Score

Modified Centor (McIsaac) criteria for sore throat. Estimates likelihood of Group A Strep pharyngitis.

📋 Source: Modified Centor Score (McIsaac et al., 1998). Used to estimate probability of Group A Streptococcal pharyngitis. Referenced in Therapeutic Guidelines: Antibiotic.
Your doctor or healthcare provider knows your history and circumstances — always follow their personalised advice over general information.

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Tonsillar exudates or swelling

White or yellow patches on the tonsils, or visibly enlarged/inflamed tonsils.

Tender anterior cervical lymphadenopathy

Tender, swollen lymph nodes at the front of the neck (anterior triangle).

Fever > 38°C (history or measured)

Temperature above 38°C, or reliable history of fever.

Absence of cough

Cough suggests a viral cause. Score 1 point if cough is absent.

Age modifier (McIsaac)

Modified Centor Score

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Australian context: Routine throat swabs and antibiotics for sore throat are not recommended for most Australians. However, Aboriginal and Torres Strait Islander patients (especially children aged 5–14 in high-risk communities) should be treated empirically if GAS pharyngitis is suspected, due to the risk of acute rheumatic fever.

First line: Phenoxymethylpenicillin (Penicillin V) 500mg BD for 10 days (children: 15mg/kg up to 500mg BD).

Penicillin allergy (non-anaphylaxis): Cefalexin 1g BD for 10 days.

Penicillin allergy (anaphylaxis/severe): Azithromycin 500mg daily for 5 days.

Rheumatic fever prophylaxis: Benzathine penicillin G IM (Bicillin LA) as per RHDAustralia guidelines for high-risk patients.

Source: Centor RM et al. (1981), McIsaac WJ et al. (1998). Therapeutic Guidelines (Antibiotic). RACGP Clinical Guidelines.