Christenson R H, Studenberg S D, Beck-Davis S, Sedor F A
Clin Chem. 1987 Apr;33(4):606-8.
Digoxin determined in the Abbott "TDx" by fluorescence polarization immunoassay by the manufacturer's recommended method involving precipitation of protein with 5-sulfosalicylic acid (SSA) is subject to interference from endogenous compounds having digoxin-like immunoreactivity. Guided by the work of Graves et al. (Clin Chem 1986;32:1506-9), we eliminated interference caused by digoxin-like immunoreactivity by substituting ultrafiltration for precipitation with SSA to remove protein. Using the manufacturer's method, we quantified digoxin in serum from 53 patients in three clinically defined groups who were receiving no digoxin, finding apparent digoxin in excess of the 200 ng/L detection limit in 24% of the 17 pregnant women, 59% of the 17 renal-dialysis patients, and all of 19 neonatal cord-blood samples examined. No measurable digoxin immunoreactivity was observed by fluorescence polarization immunoassay for any of the 53 clinically defined patients after removal of protein by ultrafiltration. For 22 men for whom digoxin was prescribed, digoxin measurement after protein removal by SSA and by ultrafiltration correlated well (r = 0.98), with good proportionality (slope = 1.04). Analytical recovery of added digoxin from adulterated serum was 115% after SSA, but 100% after ultrafiltration. Thus, before this assay procedure, we recommend ultrafiltration, to remove digoxin-like interference.
采用制造商推荐的方法，通过荧光偏振免疫分析法在雅培“TDx”中测定地高辛，该方法涉及用5-磺基水杨酸（SSA）沉淀蛋白质，易受到具有地高辛样免疫反应性的内源性化合物的干扰。在Graves等人（《临床化学》1986年；32:1506 - 9）工作的指导下，我们用超滤替代SSA沉淀法去除蛋白质，从而消除了地高辛样免疫反应性引起的干扰。我们采用制造商的方法，对来自三个临床定义组的53例未接受地高辛治疗患者的血清中的地高辛进行定量分析，发现在17例孕妇中有24%、17例肾透析患者中有59%以及所检测的19份新生儿脐带血样本中，所有样本的表观地高辛均超过200 ng/L的检测限。通过超滤去除蛋白质后，在这53例临床定义的患者中，采用荧光偏振免疫分析法均未观察到可测量的地高辛免疫反应性。对于22例开具了地高辛处方的男性患者，经SSA和超滤去除蛋白质后，地高辛测量结果具有良好的相关性（r = 0.98），且比例关系良好（斜率 = 1.04）。从掺假血清中添加的地高辛，经SSA处理后的分析回收率为115%，而经超滤处理后为100%。因此，在采用该检测程序之前，我们建议采用超滤来消除地高辛样干扰。
