The presence of all four variables indicates a 40 - 60% positive predictive value for a culture of the throat to test positive for Group A Streptococcus bacteria. The absence of all four variables indicates a negative predictive value of greater than 80%3. The high negative predictive value suggests that the Centor Criteria can be more effectively used for ruling out streptococcal throat infection than for diagnosing streptococcal throat infection.
Antibiotics: Phenoxymethylpenicillin remains first line due to its high effectiveness, no reported resistance, and narrow spectrum of activity. In the event of non-availability, amoxicillin, macrolides and cefalexin are alternative agents in decreasing preference. Antibiotic treatment length for sore throat should follow NICE guidance. For phenoxymethylpenicillin: Five days of phenoxymethylpenicillin may be enough for symptomatic cure, but a 10-day course may increase the chance of microbiological cure
See also the FeverPAIN Score