More on determination of ionized calcium in blood with ion-selective electrodes.

444 CLINICALCHEMISTRY, Vol. 33, No. 3, 1987 used for “SuperSTAT” bedside testing, as suggested by Ng et al. (1), this temperature bias must be taken into consideration. For example, mixing a sample by rolling the container between the palms should be avoided because this also will affect the sample temperature. Finally, the influence of different control-sample temperatures on precision (e.g., quality-control plots) should be stated explicitly by the manufacturer in the product information. Making this emphasis in product documentation will be helpful because the instrument is being marketed for use by nontechnical operators.