McPhaul L, Kershaw M, Tilque D, Eckfeldt J H
Clin Chem. 1985 Jul;31(7):1229-31.
Comparison of total bilirubin quantification by a 2,4-dichlorophenyl diazonium method (2,4-DCPD) with a Jendrassik-Grof type of method showed excellent correlation for randomly selected sera. However, sera from uremic patients on chronic hemodialysis showed a marked positive bias for the 2,4-DCPD result as compared with the Jendrassik-Grof result. The mean difference was 5.3 mg/L, and resulted in about 20% of the hemodialysis patients having bilirubin values greater than 13 mg/L, the upper limit of our reference range. Indican in uremic sera reportedly reacts with certain diazo reagents, so we investigated indican's reactivity in the above methods. In vitro addition of indican caused no interference in the Jendrassik-Grof method, but produced a significant positive interference in the 2,4-DCPD method, 1 mmol of indican per liter appearing as about 36 mg of total bilirubin per liter. Long reaction times with the 2,4-DCPD reagent accentuate the problem. By shortening the reaction time with the 2,4-DCPD reagent to 1.7 min, we find that the indican interference can be eliminated, without affecting quantification of total bilirubin in either normal or uremic sera.
通过2,4-二氯苯基重氮法（2,4-DCPD）与Jendrassik-Grof类型方法对总胆红素进行定量比较，结果显示随机选取的血清具有良好的相关性。然而，与Jendrassik-Grof结果相比，慢性血液透析的尿毒症患者血清的2,4-DCPD结果存在明显的正偏差。平均差异为5.3 mg/L，导致约20%的血液透析患者胆红素值大于13 mg/L，即我们参考范围的上限。据报道，尿毒症血清中的吲哚酚与某些重氮试剂发生反应，因此我们研究了吲哚酚在上述方法中的反应性。在体外添加吲哚酚对Jendrassik-Grof方法无干扰，但在2,4-DCPD方法中产生显著的正干扰，每升1 mmol的吲哚酚相当于每升约36 mg的总胆红素。与2,4-DCPD试剂的长时间反应会加剧这个问题。通过将与2,4-DCPD试剂的反应时间缩短至1.7分钟，我们发现可以消除吲哚酚的干扰，且不影响正常或尿毒症血清中总胆红素的定量。
