Gorham J D, Walton K G, McClellan A C, Scott M G
Department of Pathology, Washington University Medical Center, St. Louis, MO 63110.
Ther Drug Monit. 1994 Jun;16(3):277-80. doi: 10.1097/00007691-199406000-00008.
Using patient samples (n = 175) collected in our clinical chemistry laboratory, we have undertaken an analysis of a new colorimetric dry slide-based serum lithium (Li+) assay from Eastman Kodak for its Ektachem instrumentation series. Analyzer imprecision was acceptable, and good correlation was seen between the Ektachem assay and an ion-selective electrode (ISE)-based assay currently in use in our laboratory (r = 0.99). At all concentrations tested, potassium (K+), triglycerides, or bilirubin did not detectably interfere with the Ektachem determination of Li+. At concentrations within the reference range (135-145 mmol/L), sodium (Na+) did not affect the Ektachem Li+ determination. A slight Na(+)-dependent positive bias in the Li+ determination was evident at 157 mmol/L, but became clinically significant (> or = 0.2 mmol/L) only at physiologically extreme concentrations (> 188 mmol/L) of Na+. Very high concentrations (> 325 mg/dl) of hemoglobin also were found to cause a clinically significant positive bias. We conclude that the determination of Li+ by the Kodak Ektachem is precise, accurate, and adequately free from bias due to common interferents or other monovalent cations, and, therefore, is an acceptable alternative to currently available methods for the monitoring of serum LI+.
我们使用在临床化学实验室收集的患者样本（n = 175），对伊士曼柯达公司为其Ektachem仪器系列推出的基于比色干片的新型血清锂（Li+）测定法进行了分析。分析仪的不精密度可以接受，并且在Ektachem测定法与我们实验室目前使用的基于离子选择性电极（ISE）的测定法之间观察到良好的相关性（r = 0.99）。在所有测试浓度下，钾（K+）、甘油三酯或胆红素均未对Ektachem法测定Li+产生明显干扰。在参考范围内的浓度（135 - 145 mmol/L）时，钠（Na+）不影响Ektachem法测定Li+。在157 mmol/L时，Li+测定中存在轻微的钠（+）依赖性正偏差，但仅在生理极端浓度（> 188 mmol/L）的钠时才具有临床意义（>或 = 0.2 mmol/L）。非常高的血红蛋白浓度（> 325 mg/dl）也被发现会导致具有临床意义的正偏差。我们得出结论，柯达Ektachem法测定Li+精确、准确，并且由于常见干扰物或其他单价阳离子而充分无偏差，因此，是目前用于监测血清锂的可用方法的可接受替代方法。
