Das Sarma J, Duttagupta C, Ali E, Dhar T K
Indian Statistical Institute, Calcutta, India.
J Immunol Methods. 1995 Jul 17;184(1):7-14. doi: 10.1016/0022-1759(95)00068-l.
A new and simple method for enzyme immunoassay of folic acid (FA) has been developed, which does not require extraction or heat denaturation of serum. FA-free serum for standards was prepared by a new immunosorbent technique as conventional methods were unsuccessful. The detection limit of the assay is 0.05 ng/ml. Intra- and interassay variabilities ranged between 5-13.3%. Analytical recoveries obtained after spiking with different amounts of FA ranged between 93-110%. We eliminated the interference of endogenous folate binding protein--a major problem in direct FA assay by incubating serum samples (or standards) with FA-HRP conjugate in antibody coated plates at 50 degrees C. Comparison of our data with results obtained by microbiological assay and also by heating samples in alkaline buffer showed good correlation.
已开发出一种新的、简单的叶酸（FA）酶免疫测定方法，该方法不需要对血清进行提取或热变性处理。由于传统方法未成功，因此采用一种新的免疫吸附技术制备了用于标准品的无叶酸血清。该测定方法的检测限为0.05 ng/ml。批内和批间变异系数在5%-13.3%之间。加入不同量的叶酸后得到的分析回收率在93%-110%之间。通过在50℃下于包被抗体的平板中用FA-HRP缀合物孵育血清样品（或标准品），我们消除了内源性叶酸结合蛋白的干扰——这是直接叶酸测定中的一个主要问题。将我们的数据与通过微生物测定以及在碱性缓冲液中加热样品所获得的结果进行比较，显示出良好的相关性。
