Zweens J, Frankena H
J Clin Chem Clin Biochem. 1981 Sep;19(9):919-24. doi: 10.1515/cclm.1981.19.9.919.
A new method for the spectrophotometric determination of Evans Blue in plasma is presented. The method is based on the precipitation of the non-albumin fraction of the plasma proteins with polyethylene glycol, in order to eliminate the variable background absorption of plasma at the wavelength of maximum absorbance of Evans Blue. The accuracy and precision of the method is excellent: at an Evans Blue concentration in plasma of 5 mg . 1(-1) the coefficient of variation of the method is less than 1%. Five different procedures currently in use for the calculation of the plasma volume from the amount of indicator injected and the concentration at zero time (c0) were compared. Extrapolation to zero time of the early part (10 to 60 min) of the log concentration vs time curve turned out to the the best method for the calculation of c0, and hence yields the best estimate of the plasma volume.
提出了一种分光光度法测定血浆中伊文思蓝的新方法。该方法基于用聚乙二醇沉淀血浆蛋白的非白蛋白部分，以消除血浆在伊文思蓝最大吸收波长处的可变背景吸收。该方法的准确度和精密度极佳：血浆中伊文思蓝浓度为5 mg·L⁻¹时，该方法的变异系数小于1%。比较了目前用于根据注入指示剂的量和零时间浓度（c0）计算血浆容积的五种不同程序。结果表明，对数浓度对时间曲线早期部分（10至60分钟）外推至零时间是计算c0的最佳方法，因此能得出对血浆容积的最佳估计值。
