Gowans E M, Fraser C G
Clin Chem. 1986 Aug;32(8):1560-2.
We compared frequently used methods for calcium in urine with respect to linearity, analytical recovery, within- and between-batch imprecision, bias, and practicability. We assayed serum, lyophilized urine, native urine, and an aqueous reference solution of calcium carbonate. We found that atomic absorption spectrometry and the Corning 940 Analyzer have the widest ranges of linearity; the methylthymol blue method has the poorest analytical recovery. All methods--the aforementioned three plus the Du Pont aca and Technicon RA-1000 methods--had acceptable precision, although random errors were found with the methylthymol blue method, and, except for one type of commercial lyophilized urine assayed by the Technicon method, there were no matrix problems or difficulties with bias. We cannot recommend the methylthymol blue method, but evidently urinary calcium assays can be adequately done with many currently available methods. Intralaboratory attention to methodology should give improved performance in assessment programs.
我们比较了常用的尿钙检测方法在线性、分析回收率、批内和批间不精密度、偏差及实用性方面的情况。我们检测了血清、冻干尿、天然尿以及碳酸钙水溶液标准品。我们发现，原子吸收光谱法和康宁940分析仪的线性范围最宽；甲基百里香酚蓝法的分析回收率最差。所有方法（上述三种方法加上杜邦aca法和Technicon RA - 1000法）的精密度均可接受，尽管甲基百里香酚蓝法存在随机误差，并且除了用Technicon法检测的一种商用冻干尿外，不存在基质问题或偏差方面的困难。我们不推荐甲基百里香酚蓝法，但显然目前许多可用方法都能充分完成尿钙检测。实验室内部对方法的关注应能在评估项目中提高检测性能。
