Bowers G N, Brassard C, Sena S F
Clin Chem. 1986 Aug;32(8):1437-47.
This article reviews key advances in ion-selective electrode technology that have made potentiometric measurements of ionized calcium (Ca2+) reliable and precise. Our use of two second-generation Ca2+ analyzers (Radiometer ICA1 and NOVA 8) made possible uninterrupted service as volume increased to 31 640 patient tests in 1985. The lower results on the NOVA 8 were adjusted upwards to match those of the ICA1 to give identical results. Both analyzers were evaluated under working conditions of high volumes and multiple operators to establish downtime, electrode life, and costs. We have classified all Ca2+ analyzers into first-, intermediate-, and second-generation instruments, the better to understand their differences. Results for large numbers of patients' sera were shown to be systematically different when any two analyzers were compared. These differences are the consequence of each manufacturer's unique choices of the following: (a) the matrix of the calcium calibration solutions, (b) the type and configuration of the reference electrode, and (c) the salt-bridge solution. Elimination of each analyzer's biases will require agreement on a reference system that defines the accuracy of Ca2+ measurements on serum, plasma, or whole blood. The sound analytical performance of today's second-generation Ca2+ analyzers has allowed us to exploit the inherent superiority of Ca2+ over total calcium (CaT) measurements in the daily care of patients. We report on the preference of Ca2+ over CaT by physicians at our hospital since the introduction of second-generation Ca2+ analyzers. Therefore, we state unequivocally from our very satisfactory experience over the past five years that Ca2+ is a clinical laboratory test whose time has come!
本文回顾了离子选择性电极技术的关键进展，这些进展使离子钙（Ca2+）的电位测量变得可靠且精确。我们使用两台第二代Ca2+分析仪（Radiometer ICA1和NOVA 8），随着1985年检测量增加到31640例患者检测，实现了不间断服务。将NOVA 8较低的检测结果向上调整，以使其与ICA1的结果匹配，从而得到相同的结果。在高检测量和多名操作人员的工作条件下对这两台分析仪进行了评估，以确定停机时间、电极寿命和成本。我们将所有Ca2+分析仪分为第一代、中间代和第二代仪器，以便更好地理解它们之间的差异。当比较任意两台分析仪时，大量患者血清的检测结果显示存在系统性差异。这些差异是由于每个制造商在以下方面的独特选择造成的：（a）钙校准溶液的基质，（b）参比电极的类型和配置，以及（c）盐桥溶液。要消除每种分析仪的偏差，需要就一个参考系统达成一致，该系统定义了血清、血浆或全血中Ca2+测量的准确性。当今第二代Ca2+分析仪良好的分析性能使我们能够在患者的日常护理中利用Ca2+相对于总钙（CaT）测量的固有优势。我们报告了自引入第二代Ca2+分析仪以来我院医生对Ca2+相对于CaT的偏好。因此，基于我们过去五年非常满意的经验，我们明确指出，Ca2+是一项临床实验室检测，其时代已经到来！
