A simple scorecard for the tentative diagnosis of streptococcal pharyngitis.

More than 20,000 acute respiratory illnesses of children were studied by physicians in private practice to derive a nine-factor scorecard designed to estimate the probability that a given child's respiratory illness is caused by beta-hemolytic streptococci. Each factor was assigned a weight on the basis of the percentage of positive cultures from patients exhibiting that factor. The sum of these individual scores gave the total score. The higher a patient's score, the more probable was a streptococcal infection. Thus, depending on the score, a reasonably accurate prediction of the probability of a streptococcal infection can be made. The accuracy of such predictions compared favorably with that of skilled physicians.