The ion selective electrode method (ISE) for concentration measurement of the ionized calcium has an effect on the measured sample's matrix being large in the same manner as sodium and potassium measurement. Accordingly, measured values by the ISE have differences due to the measurement system. The certified serum reference material (CRM), as the certified matrix reference material, was established for the correction of results of ISE to utilize the ISE in a better way. The certified value of the ionized calcium is measured by using the Covington-Umemoto cell as the reference standard cell system. This CRM can be solved the problems which results in differences in the measured values between device or facilities.
This document offers a protocol the theory of setting the CRM, the data correction, sampling, transport, storage and clinical application.
