Figure 1.

The screen shot (from a "test" patient in the "test" EHR) shows the stealth alert generated for patients in the post-intervention period. Whenever a patient enrolled in the anticoagulation management service (AMS) received a prescription for a medication that could potentially interact with warfarin (see Table 1), this stealth alert was generated in the InBasket (left side of the screen) of the AMS nurse, who would then contact the patient to arrange appropriate follow-up of the international normalized ratio (INR).