枸橼酸钠使ELISA的检测值升高

目的血浆交换（ＰＰ）前血乙酰胆碱受体抗体（ＡＣｈＲＡｂ）滴度高，重症肌无力（ＭＧ）病情重；交换后病情减轻，但血中此抗体反而更高。抗体测定中，交换前用的是血清，交换后用血浆。本研究旨在探讨抗凝剂枸橼酸钠对用ＥＬＩＳＡ法测定血中ＡＣｈＲＡｂ滴度是否有干扰作用。方法对４５例未经ＰＰ的ＭＧ患者血清、血浆和加枸橼酸钠血清中的ＡＣｈＲＡｂ滴度用ＥＬＩＳＡ进行检测、比较，并对３例ＰＰＭＧ患者在ＰＰ前后及不同时间采血进行检测并比较。结果血浆及加枸橼酸钠血清中ＡＣｈＲＡｂ滴度均显著高于血清中者（Ｐ＜０．０１），且ＰＰ前后及不同采血时间血清中的ＡＣｈＲＡｂ滴度有所改变。结论枸橼酸钠可使ＥＬＩＳＡ的背景着色加深，有正向干扰作用。建议凡ＥＬＩＳＡ检测均应尽量用血清而非血浆。

Sodium Citrate Causes Higher AChRAb Value in ELISA Determinations

Objective Acetylcholine receptor antibody (AChRAb) titer tested by ELISA in MG patient's blood was an useful routine measure of therapeutic importance during plasmapheresis. The question whether sodium citrate could influence the result of ELISA was investigated. Methods AChRAb was determined by routine ELISA and compared in serum, plasma and serum added with sodium citrate in 45 patients with MG treated by methods other than plasmapheresis. Plasmapheresis (PP) was performed in 3 patients with MG. Blood was withdrawn in this 3 patients before PP and at different time points after PP. Results AChRAb determined in plasma and serum added with sodium citrate was statistically significant ( P <0 01). Titers of AChRAb before plasmapheresis and different time after plasmapheresis was decreased significantly than that in serum, and serum plus sodium citrate. Conclusion Sodium citrate increased the background staining of ELISA. Therefore, Serum was recommendated for the routine determination of ELISA.