Validation of automated event triggers using laboratory values related to two problem-prone drugs.

We used computerized alerts to identify patients with laboratory values that could be related to medication errors associated with digoxin and warfarin. Over a six-week period at two inpatient facilities, we generated 62 laboratory-based alerts for warfarin, and 66 for digoxin. The positive predictive value for these alerts representing a preventable event was 71% and 57% for warfarin and digoxin, respectively.