To Err Is Human: Part 4 - How "Missing the Point" When Writing Prescription Orders Can Result in 10-Fold Medication Errors

Presenting the fourth installment of Dr. Laura Bauman’s To Err Is Human series, which focuses on common errors in nuclear medicine that may occur during the process of writing, ordering and/or filling prescriptions. The series also emphasizes the critical importance for organizations to establish error prevention strategies.

This installment addresses errors that can occur using trailing zeros and naked decimal points when writing prescription orders. As usual, Dr. Bauman also suggests ways to avoid these all-too-common errors.

Those “unnecessary zeros” after a decimal point that do not affect the value of the number — which are called “trailing zeros” — can often cause more harm than good. It is not uncommon for readers to overlook the decimal point when it is followed by a zero and, thus, multiply the intended dose by 10. Trailing zeros are a frequent cause of these types of 10-fold medication errors, which can cause patient harm or even death.

On the flip side, forgetting a zero before the decimal point may also cause a 10-fold medication error. Writing .5 instead of 0.5 is called a “naked decimal point”. Placing a zero before the decimal point helps to pull readers' attention to the decimal point to avoid this error.

Lessons Learned

This is similar to what occurred when a nuclear medicine technologist sent a fax order form for a custom compounded I-131 capsule. The pharmacists typed, reviewed and dispensed the order for “20 mCi”. The next day, the technologist called to complain that the 2 mCi whole body scan iodine capsule was reading way too hot. Upon review of the low-quality fax order form, the pharmacists noticed that there were several grainy spots between the two and the zero that could have been intended to be a decimal point but were dismissed due to the large number of grainy spots throughout the entire fax form and the clarity of the zero.

Fortunately, the technologist assayed the capsule before administering the higher dose to the patient. Another custom capsule was made and immediately sent so the patient could be dosed on the same day.

To prevent this type of error from occurring again, the technologists and pharmacists agreed to several processes. First, the technologists agreed to write both the textual and numerical value for the requested activity for all iodine doses on fax order forms. Second, they agreed to omit any unnecessary zeros, or trailing zeroes, in the numerical value; and, third, to write out the procedure for each dose. With these safety processes in place, the next order would clearly read as follows: “2 (two) mCi I-131 whole body scan.”

As an additional precaution, the pharmacists agreed to call to confirm any orders not following the new processes as well as any unclear orders on grainy low quality faxes. For example, if the pharmacist received a fax order for a “20 mCi I-131 whole body scan”, they would call to confirm the activity since there was not a textual value written and 20 mCi is a large dose for a whole body scan.

Instituting Best Practices

The Institute for Safe Medication Practices (ISMP), the Joint Commission (TJC) and many other organizations (perhaps including your own!) encourage the avoidance of trailing zeros and naked decimal points. Although 10-fold errors are widespread for other prescription medications, there are few products in nuclear medicine with appropriate doses across a 10-fold span. Together, technologists and pharmacists can be mindful to these few products, like custom compounded iodine capsules or sodium pertechnetate doses, by using zeros before but not after the decimal point.

Click here for more examples of ISMP's list of error-prone abbreviations, symbols and dose designations.

 — Stay tuned for Dr. Bauman’s next Industry Insider Blog installment in the To Err Is Human series on how the use of strikeouts and other Good Documentation Practices can help prevent medication errors when writing prescription orders.

Our Online Prescription Ordering System can help your nuclear medicine department avoid many of the common communication mistakes that lead to dispensing errors. Now available through our pharmacies nationwide, Online Prescription Ordering provides a quick, easy and secure way to transmit your prescription orders directly to your local pharmacy. Contact your  Jubilant Radiopharma Radiopharmacies Division pharmacist to register today.