Frequency of extreme differences and clinical performance of glucose concentration measurements judged from 21 000 duplicate measurements

摘要

Duplicate measurements of patient samples are not common in routine clinical chemistry. The performance of measurements is continuously monitored by the internal quality control (IQC),1 which is not designed to find occasional dropouts. Therefore, the frequency of such errors is not usually known. In the present study, we attempted to estimate the error frequency at commonly suggested imprecision targets by evaluating the difference between 2 adjacent repeated measurements. The frequency is expected to be very low, and therefore the study of this problem required a large number of samples.