Adverse events after hospital discharge are a continued threat to patient safety and the basis for interventions targeting key contributing factors. Premature discharge is an area less studied, partly because the decision-making for safe discharge falls on individual providers and their clinical assessment. This study developed a set of triggers based on selected laboratory abnormalities that could systematically identify patients potentially unsafe for discharge. Triggers that led to a discharge alert included an elevated white blood cell count, a rising creatinine level, specific abnormalities in electrolytes, and an elevated international normalized ratio (INR) in the absence of anticoagulant therapy. The discharge filter tool requires further validation, but it represents an innovation that leverages computerized systems to provide safer care.