Medication-error alerts for warfarin orders detected by a bar-code-assisted medication administration system

Medication-error alerts for warfarin orders detected by a bar-code-assisted medication administration (BCMA) system were evaluated.

All patients receiving warfarin who were admitted to a university medical center between July 1, 2008, and February 6, 2009, in inpatient units with BCMA systems were candidates for inclusion in this study. Medication-error alerts displayed to the nurse administering the warfarin were reviewed to determine whether a true potential error was detected. Each alert was converted to a scenario, and its potential to require treatment or cause patient harm was rated using a validated severity scale of 0-10, where a score of 0 indicated no probable effect on the patient and 10 indicated that the error would likely result in patient death. A severity score was obtained by averaging the scores of four pharmacist reviewers.

Of the 18,393 warfarin doses ordered during the study period for 2,404 patients, error alerts associated with only 99 warfarin doses were found to be clinically meaningful. The mean ± S.D. severity rating of these alerts was low (2.93 ± 1.42), with a standardized Cronbach's coefficient alpha of 0.845. The mean ± S.D. warfarin dose attempted when the nurse received an alert was 4.10 ± 2.48 mg. The majority of doses with alerts (70%) were for patients who had an active order for warfarin.

Of the large number of medication-error alerts generated through a BCMA system, only a small proportion were considered clinically significant. This indicated that the rate of false-positive alerts was unexpectedly high, increasing the risk of alert fatigue.