Diagnostic errors are unwanted clinical events that place patients at risk for injury. The authors have previously reported that a majority of congenital echocardiography errors have clinical impacts and, on the basis of a small cohort, identified factors associated with diagnostic error. The objectives of this study were (1) to evaluate patient risk factors for diagnostic errors in a large contemporary cohort and (2) to identify risk factors for situation-related diagnostic errors.

Diagnostic errors were identified at a large academic pediatric cardiac center from 2004 to 2011. Clinical and situational variables were collected from diagnostic error cases and controls.

Among the 254 diagnostic error cases, 66% affected clinical management or patients experienced adverse events; 77% of errors were preventable or possibly preventable. Coronary arteries, pulmonary veins, and the aortic arch were most commonly involved with diagnostic errors. Multivariate analysis identified the following patient-related risk factors: rare or very rare diagnoses (adjusted odds ratio [AOR], 6.3; P < .001), high anatomic complexity (AOR, 3.4; P < .001), and weight < 5 kg (AOR, 2.7; P < .001). Risk factors related to the setting of the echocardiographic study included evening or night (7 pm to 6:59 am) study interpretation (AOR, 2.6; P = .005) and weekend studies (Friday through Sunday) (AOR, 1.6; P = .04). The model area under the receiver operating characteristic curve was 0.833.

In addition to patient risk factors, the setting of an echocardiographic study and interpretation contribute to risk for a diagnostic error. Studies interpreted overnight or performed during a weekend should be considered for a quality improvement activity to reduce diagnostic errors or their impact.