Diagnostic criteria and efficient use of outpatient cultures.

The authors conducted an eight-year longitudinal study to evaluate the effect of diagnostic criteria on efficient use of outpatient cultures. Efficiency was determined by monitoring alterations in culture use, yield (percent positive), and charges for four common ambulatory diseases: Group A streptoccocal pharyngitis; gonococcal urethritis and cervicitis; bacterial cystourethritis; and acute enterocolitis.The study demonstrated that the use of diagnostic criteria resulted in more efficient use of laboratory tests as reflected in the immediate and sustained decrease in culture use and associated charges, an increase in yield (percent positive), and a corresponding decrease in charge per test.