<qa>  How many signs and symptoms did Centor use to estimate the probability of acute streptocoThe original Centor score uses four signs and symptoms to estimate the probability of acute streptococcal pharyngitis in adults with a sore throat.4 The score was later modified by adding age and validated in 600 adults and children.5,6 The cumulative score determines the likelihood of streptococcal pharyngitis. 