De Sadeleer Carlos, Piepsz Amy, Ham Hamphrey R
Department of Radioisotopes, CHU St. Pierre, Brussels, Belgium.
Ann Nucl Med. 2006 Feb;20(2):95-8. doi: 10.1007/BF02985620.
The aim of the present work was to evaluate two classical formulae allowing the correction for having neglected the first exponential in the slope-intercept method used for the determination of EDTA clearance, namely the Chantler's linear correction formula (CH) and the Bröchner-Mortensen's quadratic correction formula (BM). First, a comparison study was performed with the two correction formulae, in order to predict the behavior of the calculated clearance, for various levels of renal function. Second, using data obtained from 47 adult patients with normal renal function, the results obtained with the two correction formulae have been compared to the reference technique, namely the biexponential fit. The results of the comparison study indicated that for clearance values lower than 120 ml/min, the results obtained using CH were systematically lower than those of BM, whereas for clearance values between 120 and 140 ml/min, the reverse was observed. The differences however, never exceeded 8 ml/min. The results were quite different when the clearance was higher than 140 ml/min, when the difference between CH and BM results increased rapidly, and the BM provided values systematically lower than CH. The clinical study showed that, in the range of normal clearance values, both CH and BM clearances were slightly lower than the results obtained by means of the reference technique. Based on these results, a new specifically designed validation study involving patients with high clearance values is mandatory to determine which of these two correction methods is more accurate, or to devise a better correction formula.
本研究的目的是评估两个经典公式，这两个公式用于校正因在用于测定EDTA清除率的截距法中忽略了第一个指数而产生的误差，即钱特勒线性校正公式（CH）和布勒克纳-莫滕森二次校正公式（BM）。首先，对这两个校正公式进行了比较研究，以预测在不同肾功能水平下计算得到的清除率的表现。其次，使用从47名肾功能正常的成年患者获得的数据，将这两个校正公式得到的结果与参考技术（即双指数拟合）进行了比较。比较研究的结果表明，对于清除率值低于120 ml/min的情况，使用CH得到的结果系统性地低于BM的结果，而对于清除率值在120至140 ml/min之间的情况，则观察到相反的结果。然而，差异从未超过8 ml/min。当清除率高于140 ml/min时，结果有很大不同，此时CH和BM结果之间的差异迅速增大，且BM提供的值系统性地低于CH。临床研究表明，在正常清除率值范围内，CH和BM清除率均略低于通过参考技术获得的结果。基于这些结果，必须开展一项专门针对高清除率值患者设计的新验证研究，以确定这两种校正方法中哪一种更准确，或者设计出一个更好的校正公式。
