Streptococcal disease control in an ambulatory practice. Explicit criteria for throat cultures.

A throat culture protocol was implemented in an ambulatory practice to standardize culturing and to conserve laboratory resources. A retrospective chart audit during three one-month study periods preceding (1976) and following protocol implementation (1978 and 1979) showed a significant effect on care-provider compliance with culture criteria (P<.0001). During a three-year period there was a significant decrease in the number of cultures done for patients younger than 2 years of age (23.6%, 6.9% and 0%; P<.001) and asymptomatic patients (19.4%, 13.9% and 3.1%; P<.001). From 1976 to 1978 there was a 50% decrease in cultures per 100 visits (12.3 versus 6.0). This change resulted in a three-year cost savings of $79,944. Of interest was the significant increase in the percentage of positive cultures between 1977 and 1978 (12.0% versus 18.8%; P<.001). This latter finding suggests that culture protocol criteria were selective for patients with pathogens.