Yao H, Jenkins S H, Pesce A J, Halsall H B, Heineman W R
Biomedical Chemistry Research Center, University of Cincinnati, OH 45221-0172.
Clin Chem. 1993 Jul;39(7):1432-4.
We demonstrate here an electrochemical homogeneous enzyme immunoassay for theophylline, which can be performed in hemolyzed, lipemic, and icteric samples. The assay used an unmodified Syva EMIT theophylline kit. One of the enzymatic reaction products, NADH, reacted with 2,6-dichloroindophenol (DCIP) to reduce DCIP to DCIPH2, which was detected electrochemically with flow-injection analysis. The inter- and intraassay coefficients of variation of this manual technique were < 9% at theophylline concentrations of 14 to 34 mg/L. The CVs were 9-15% at low concentrations (6.3 mg/L), which is below the therapeutic range. Analytical recoveries were 91-97% for normal serum and 92-111% for hemolyzed, icteric, or lipemic sera. The measured concentrations (y) were compared with those obtained by the fluorescence polarization immunoassay (x); a scatter plot of the results showed a linear relationship of y = 1.00 x - 0.57 mg/L (r = 0.966, Sy/x = 1.51). This alternative way to measure the serum concentration of theophylline overcomes the shortcomings of spectrophotometric methods, by which it is difficult to measure theophylline in severely hemolyzed, icteric, or lipemic sera.
我们在此展示一种用于茶碱的电化学均相酶免疫测定法，该方法可在溶血、脂血和黄疸样本中进行。该测定使用了未改性的Syva EMIT茶碱试剂盒。酶促反应产物之一NADH与2,6 - 二氯靛酚（DCIP）反应，将DCIP还原为DCIPH2，通过流动注射分析对其进行电化学检测。在茶碱浓度为14至34 mg/L时，该手工技术的批间和批内变异系数<9%。在低浓度（6.3 mg/L）时变异系数为9 - 15%，此浓度低于治疗范围。正常血清的分析回收率为91 - 97%，溶血、黄疸或脂血血清的分析回收率为92 - 111%。将测得的浓度（y）与通过荧光偏振免疫测定法获得的浓度（x）进行比较；结果的散点图显示y = 1.00 x - 0.57 mg/L的线性关系（r = 0.966，Sy/x = 1.51）。这种测量血清茶碱浓度的替代方法克服了分光光度法的缺点，分光光度法难以在严重溶血、黄疸或脂血血清中测量茶碱。
