Liedtke R J, Kroon G, Batjer J D
Clin Chem. 1981 Dec;27(12):2025-8.
We describe an automated method for calcium assay, for use with the Cobas-Bio centrifugal analyzer. Calcium is reacted with cresolphthalein complexone and the absorbance of the calcium--dye complex at 575 nm is measured. EDTA is then added to break up the calcium--dye complex and the absorbance at 575 nm is re-measured, to correct for endogenous color and turbidity. Day-to-day precision data, determined over four months, were as follows: mean = 92.9 mg/L, CV = 1.47%; n = 216; mean = 128.7 mg/L, CV = 1.72%; n = 216. Comparison of the Cobas-Bio method (y) with an atomic absorption spectrometric method (x) gave the following results: y = 1.012x--2.05, r = 0.991, Sy/x = 1.2, mean x = 92.63 mg/L, mean y = 91.69 mg/L, n = 74. Hemoglobin, bilirubin, or turbidity does not interfere. At the medical decision value (110 mg/L), the overall analytical error is 4.6 mg/L, which is less than the 5 mg/L allowable (95% confidence limit) error.
我们描述了一种用于钙测定的自动化方法，用于Cobas-Bio离心分析仪。钙与甲酚红络合剂反应，然后测量钙-染料络合物在575nm处的吸光度。接着加入乙二胺四乙酸（EDTA）以分解钙-染料络合物，并重新测量575nm处的吸光度，以校正内源性颜色和浊度。在四个月内测定的日常精密度数据如下：平均值=92.9mg/L，变异系数（CV）=1.47%；n=216；平均值=128.7mg/L，CV=1.72%；n=216。将Cobas-Bio方法（y）与原子吸收光谱法（x）进行比较，结果如下：y=1.012x-2.05，r=0.991，Sy/x=1.2，平均x=92.63mg/L，平均y=91.69mg/L，n=74。血红蛋白、胆红素或浊度不产生干扰。在医学决定值（110mg/L）时，总分析误差为4.6mg/L，小于允许的5mg/L（95%置信限）误差。
