What is your success rate at catching drug errors?

For the third month in a row the pharmacy posted on the wall in the back of the prescription department the pharmacy's success rate. This month the pharmacy's success rate (91%) broke a new barrier. It was cause for celebration.

For the third month in a row the pharmacy posted on the wall in the back of the prescription department the pharmacy's success rate. This month the pharmacy's success rate (91%) broke a new barrier. It was cause for celebration.

Three months earlier, the success rate was at a dismal 64%. Last month it was at 87%. While 91% was not where the pharmacy wanted to be, it was better than 64% or even 87%. On the wall next to the three one-month pie charts was a hand-drawn graph showing a bright red line going up from 64% to 87% to 91%.

Every pharmacy should know and post its success rate. The success rate is the percentage of prescription mistakes caught before they reached the patient. A mistake that reaches a patient is a failure, but a mistake that is caught by someone before delivery to a patient is a success. It is proof that the system works.

There are three good measures of a pharmacy's quality assurance program. The first is the percentage of errors (error rate). For the purpose of this discussion, in pharmacy an error is simply any deviation from the prescription as written that has moved from the pharmacy's control. The number of errors divided by the number of prescriptions filled in a given time gives the error rate. Whether a patient took the medication or whether any harm occurred is irrelevant. From the pharmacy viewpoint, an error occurred. Whether or not an injury resulted is a matter of luck.


Quality-related events

The second measure is the percentage of mistakes or quality-related events that were made (QRE rate). The number of mistakes divided by the number of prescriptions filled during a set time period provides the QRE rate. A QRE is any mistake regardless of whether or not it became an error by reaching a patient.

The third useful measure is the success rate. It is a simple recording of Yes or No. Yes, it did reach a patient (failure of quality) or No, it did not reach the patient (success of the system to capture mistakes).

In many ways this is the best measure and the easiest to chart. It answers the basic question, "How well is it working?" The importance of the story of the pharmacy, whose success rate increased from 64% to 91% within three months, is not just the change, but the fact that the staff knew they had improved and they could prove it.

Continuous quality improvement

A continuous quality improvement system is driven by information and a motivated staff. The problem with running a CQI program is keeping the staff focused on taking the steps necessary on a daily basis to prevent mistakes from occurring or capturing and correcting them before they reach the patient.

While some studies indicate an average QRE rate approaching 2%, my experience convinces me it is closer to one-half percent. Some 199 prescriptions go through the system without any mistakes and the staff becomes complacent. The things that worked to reduce the failure rate are now only done "some of the time." Only when a mistake is caught is the staff again motivated to complete each step in the quality workflow. There needs to be a regular reminder of the system-something that says, "You are doing great; keep it up." A monthly posting of a success rate is a good way of providing positive reinforcement, while QRE rates and error rates have a negative connotation. A success rate is positive.

One pharmacy we worked with had a consistent success rate of over 98%. What is your pharmacy's success rate? Do you have a way of measuring it? If your pharmacy is not recording near misses and errors, contact your state pharmacy association. All state pharmacy associations can provide a system inexpensively through a not-for-profit organization called the National Alliance of State Pharmacy Associations.

This article does not constitute legal or consultative risk management advice. You should not rely on the information here or in any similar article for a plan of quality or for legal matters. Consult a risk management consultant or an attorney.

THE AUTHOR practices law as an attorney, of counsel, with the Arizona law firm of Renaud Cook Drury Mesaros, PA. He also consults in the areas of pharmacy error reduction and risk management. For questions or citation and footnotes, you can contact him at