Evaluation of AVL988/4 analyzer for measurement of ionized magnesium and ionized calcium.

Ionized magnesium (Mg++) and ionized calcium (Ca++) are the physiologically active forms of these elements in the body and their concentrations have clinical value. Though the AVL988/4 instrument that measures concentrations of Mg++ and Ca++ has been evaluated, some clinically important parameters were unknown. In this study, we evaluated AVL988/4 analyzer for measuring Mg++ and Ca++ concentrations and provided the following information: (1) The newly formulated Becton Dickinson (BD) Vacutainer plastic tubes with clot activator and silicone as the stopper lubricant (serial no. 367820) caused a significant high bias for the Mg++ measurement but had no effect on the Ca++ measurement; (2) the optimal conditions for specimen storage were no exposure to air at 4 degrees C for up to 24 h; (3) no significant difference in the results of the Ca++ concentration determined using AVL988/4 or i-STAT; (4) no carryover between samples was found.