Thode J, Boyd J C, Ladenson J H
Department of Pathology, Washington University School of Medicine, St. Louis, MO 63110.
Clin Chem. 1987 Oct;33(10):1811-3.
We measured the activity of Ca2+, Na+, K+, and Cl- with ion-selective electrodes after equilibrium dialysis of solutions with different albumin concentrations. The calculated Donnan ratio was the same for all ions in the same solution and increased with the albumin concentration, as predicted by the Donnan theory. The Donnan distribution ratio for Ca2+ was similar, as determined with instruments from three different manufacturers. For healthy subjects and patients with renal stone disease, we did not find any correlation between serum concentrations of ionized calcium and albumin. The discordance between measured ionized calcium and albumin-corrected total calcium depended on the correction algorithm we utilized. The difficulties of absolutely proving or disproving a protein error in these measurements are discussed, but our data are not consistent with protein being a source of error in measurements of ionized calcium.
在用不同白蛋白浓度的溶液进行平衡透析后，我们使用离子选择性电极测量了Ca2+、Na+、K+和Cl-的活性。计算得到的唐南比率在同一溶液中的所有离子中是相同的，并且如唐南理论所预测的那样，随着白蛋白浓度的增加而增加。使用来自三个不同制造商的仪器测定的Ca2+的唐南分布比率相似。对于健康受试者和肾结石疾病患者，我们未发现血清离子钙浓度与白蛋白之间存在任何相关性。测量的离子钙与白蛋白校正后的总钙之间的不一致取决于我们使用的校正算法。讨论了在这些测量中绝对证明或反驳蛋白质误差的困难，但我们的数据与蛋白质是离子钙测量误差来源的观点不一致。
