Critical appraisal of the clinical relevance of rapid diagnosis in pediatrics.

To assess the potential impact of rapid diagnostic tests on the care of the pediatric patient a critical evaluation of the antigen detection tests currently available for two important pediatric diseases--Haemophilus influenzae type b meningitis and group A beta-hemolytic streptococcal pharyngitis--is presented. Antigen detection tests for Haemophilus influenzae type b meningitis are of value primarily as an adjunct to traditional procedures, whereas antigen detection tests for the rapid diagnosis of group A beta-hemolytic streptococcal pharyngitis could, in the near future, replace the blood agar culture. This comparison demonstrates that the evaluation of a new diagnostic test should include not only a determination of its accuracy, but, in addition, a determination of its advantages over current methods, the frequency with which the test will be performed, the consequences of a false-negative or false-positive test result, and the potential impact on patient care resulting from use of the test.