Medication selection errors made by pharmacy technicians in filling unit dose orders.

The selection errors made by pharmacy technicians in filling unit dose orders at University Hospital were recorded to determine the percentage error rate and to categorize the errors detected. Errors were categorized as "incorrect medication", "incorrect dosage", "incorrect dosage form", "omitted medication", or "'extra medication". The relationship of the number of errors with respect to individual wards and the time of medication order filling was also examined. The daily procedure in order filling did not change for the study. Errors were detected and counted after the orders had been filled by the technicians. The time the error occurred and the ward where the incorrect medication would have gone was also recorded. The overall percentage error rate was 1.7% which was consistent for the four time periods studied. However, a rate variability of 0.4 to 4.5% was detected between different wards. "Incorrect dosage" errors were the most frequently occurring errors, followed by "omitted medication", "incorrect medication", "extra medication", and "incorrect dosage form". Medication selection errors should be considered as potential administration errors which could be harmful to the patient.