Measuring the rate of manual transcription error in outpatient point-of-care testing

Abstract

Many point-of-care laboratory tests are manually entered into the electronic health record by ambulatory clinic staff, but the rate of manual transcription error for this testing is poorly characterized. Using a dataset arising from a duplicated workflow that created a set of paired interfaced and manually entered point-of-care glucose measurements, we found that 260 of 6930 (3.7%) manual entries were discrepant from their interfaced result. Thirty-seven of the 260 (14.2%) errors were discrepant by more than 20% and included potentially dangerous mistranscriptions. An additional 37 (14.2%) errors were due to inclusion of non-numeric characters. Staff-entered result flags deviated from the result flag generated in the laboratory information system in 5121 of 6930 (73.9%) pairs. These data demonstrate that clinically significant discrepancies for clinic-entered point of care results occurred at a rate of approximately 5 per 1000 results and they underline the importance of interfacing instruments when feasible.

Figure 1.

Clarke error grid comparing discrepant interfaced glucose results to manual-entry glucose results. A Clarke error grid assigns risk categories to discrepancies between 2 methods. Region A describes events within 20% of each other, whereas region B describes a discrepancy >20% but one unlikely to lead to clinical harm. Region C identifies discrepancies that may lead to unnecessary treatment. Region D describes events in which hyperglycemia or hypoglycemia was missed, and region E identifies cases in which there was outright confusion between hyperglycemia and hypoglycemia. A total of 14.2% of errors (0.5% of all events) were outside region A of the Clarke error grid, and several events had risk of mistreatment on the basis of mistranscribed values.