Takano Susumu, Kaji Hiroshi, Hayashi Fujio, Higashiguchi Kanae, Joukei Sachie, Kido Yoshiaki, Takahashi Juro, Osawa Kayo
Faculty of Health Sciences, Kobe University Graduate School of Health Sciences, Kobe, Japan.
Anal Chem Insights. 2012;7:23-30. doi: 10.4137/ACI.S9681. Epub 2012 Jul 4.
Measurement of ionized calcium is more important than measurement of total calcium in serum samples. In the present study, equations were derived from complexation and acid dissociation equilibrium equations, and were used to determine the concentration of ionized calcium from the observed serum concentrations of total calcium, albumin, total protein, and inorganic phosphate. The ionized calcium concentration was calculated in 67 serum samples from healthy subjects and 34 outpatients previously identified as having abnormal serum calcium levels. The correlation coefficient between our method (y) and the calcium-ion-selective electrode method (x) was 0.953 and the linear regression equation was y = 0.97x at pH 7.4 with a factor of α = 0.21, which was based on the differences between the concentrations of calcium phosphorus compounds obtained by the electrode method and by calculation. The developed calculation is as useful and accurate as the electrode method, and therefore extremely useful for clinical diagnoses.
在血清样本中，测量离子钙比测量总钙更为重要。在本研究中，根据络合和酸解离平衡方程推导了公式，并用于根据观察到的血清总钙、白蛋白、总蛋白和无机磷酸盐浓度来确定离子钙的浓度。计算了67例健康受试者血清样本以及34例先前被确定为血清钙水平异常的门诊患者的离子钙浓度。在pH 7.4时，我们的方法（y）与钙离子选择性电极法（x）之间的相关系数为0.953，线性回归方程为y = 0.97x，α因子为0.21，这是基于电极法和计算法所获得的钙磷化合物浓度之间的差异。所开发的计算方法与电极法一样有用且准确，因此对临床诊断极为有用。
