Evaluation of Linearity and Interference Effect on SMBG and POCT Devices, Showing Drastic High Values, Low Values, or Error Messages.

Abstract

When a patient with diabetes measures blood glucose levels using a simple blood glucose meter, an error message or abnormal value may be displayed because of interfering substances, potentially leading to unnecessary medical treatment. Here, we tested 10 self-monitoring of blood glucose (SMBG) and point-of-care testing (POCT) devices to investigate under what conditions they fail to measure blood glucose levels or display abnormal values instead. We also evaluated the influence and linearity of several well-known interfering substances and hematocrit (Ht). Each adjusted sample was measured by each device twice and the values compared with the reference values. Linearity was favorable in all but one model. The impact of the interfering substances and Ht has been confirmed in many SMBG and POCT devices. In particular, some models showed significant pseudo-high or -low levels for samples that contained ascorbic acid, which is used widely in infusion solutions. Three devices showed error messages to avoid presenting a false value. Since pseudo-high levels may result in the excessive administration of insulin and lead to adverse events, this report serves as a critical reminder of the importance of device choice for specific indications. Three new devices have safety functions that prevent the showing of false values.