Although cardiologists who treat adults have been evaluating pediatric patients using echocardiography since the early 1980s, the diagnostic accuracy of such studies has never been tested.: To prospectively assess diagnostic accuracy of pediatric echocardiograms performed in adult laboratories (adult-lab echos) compared with evaluations of the same patients in pediatric laboratories (pediatric-lab echos), we gathered data from 66 patients, ages 1 day to 18 years (median 19 months), who underwent adult-lab echos in community hospitals or private offices before evaluation by a pediatric cardiologist subsequently, 65 underwent pediatric-lab echos in a university hospital laboratory. Echocardiographic diagnoses were compared with (1) diagnoses proved by catheterization or surgery (25 patients), and (2) echocardiographic diagnoses verified by blinded duplicate-observer review (41 patients). Eighteen patients had no cardiac disease; 42 had simple lesions, 5 had intermediate lesions, and 1 had a complex lesion. In 25 patients with 46 procedure-proven diagnoses, the most important error per adult-lab echo was major in 11 (44%), moderate in 7 (28%), and minor in 3 (12%); in pediatric-lab echos it was major in 0 (0%), moderate in 1 (4%), and minor in 1 (4%). In 41 patients with 62 duplicate observer-verified diagnoses, the most important error per adult-lab echo was major in 5 (12%), moderate in 12 (29%), and minor in 5 (12%); pediatric-lab echos had no errors. In 35 of 66 adult-lab echos (53%), the mast important error was major or moderate. OF these, 71% were interpretive, 17% technical, and 11% both. Error incidences were not related to patient age, study year, use of color Doppler, or complexity of diagnoses. In 29 of these 35 patients, pediatric-lab echos resulted in altered clinical management, including 12 surgeries and 2 averted surgeries. In 3 of the 29, delayed diagnoses were associated with fixed pulmonary vascular disease, hypoxemic spells; and vascular collapse with severe metabolic acidosis. This study reveals a high incidence of diagnostic errors ih pediatric echocardiograms performed in community-based adult laboratories, despite a preponderance of patients with simple diagnoses or no heart disease. (C) 1999 by Excerpta Medico, Inc.