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There are currently two groups of devices for selfmonitoring of blood glucose (SMBG) in Japan. One group of the devices gives glucose levels close to those of venous plasma, while it uses fingertip blood as a blood sample. SMBG devices of the other group show glucose levels close to those of fingertip blood plasma. In 2003, ISO 15197 became into effect. In this document it is clearly required that measurements from SMBG devices should be comparable to reference glucose levels of the plasma portion of the same capillary blood determined by a validated measurement procedure.
A new SMBG devise, “Glucocard Diablue” or “Glutest Ace Ri” (other trade name), was evaluated for its accuracy depending on the ISO 15197 requirements. Fingertip capillary blood samples from 88 volunteer patients with diabetes mellitus were analyzed for glucose levels with the SMBG device. From the same capillary blood samples, plasma was separated by centrifugation and the glucose levels were measured using an automated analyzer.
The values of 8 samples obtained with the SMBG device with glucose levels measured below 75 mg/dl by the automated analyzer were all within ±15mg/dl, which is the allowance limit required by ISO 15197, and 98.9% of values from 94 other samples obtained with the SMBG device above 75 mg/dl, were all within ±20%, which meets the criteria of ISO 15197. In conclusion, this new device for SMBG cleared the accuracy required by ISO 15197.

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There are some inter-instrument differences in measured values by using self-monitoring of blood glucose (SMBG) devices. The reason is caused by characteristics of comparison method and kind of specimen. ISO issued the International Standard for SMBG devices (ISO 15197: 2003an vitro diagnostic test systems-Requirements for blood-glucose monitoring systems for self-monitoring in managing diabetes mellitus). I this document, the system accuracy evaluation shall be performed with at least 100 fresh capillary blood samples, each with sufficient volume to be measured by two different meters and at least in duplicate by the manufacturer's measurement procedure in this document. Capillary blood samples shall be collected by skin puncture (e.g., fingerstick), prepared and processed according to the instructions for use, including sample pre-treatment if required. Sample containers designed for the collection of capillary blood should be used. Only unaltered capillary blood samples shall be used for glucose concentrations of 2.8-22.2 mmol/l (50-400mg/dl). However, it is difficult to perform in Japan. Then the new calibration procedure instead of the system accuracy evaluation by ISO document is established by using venous whole blood by volunteers. This procedure is possible covered from low concentration level to high concentration level of glucose. It can be applied to calibration of system accuracy.

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