磁珠浓缩法在低浓度HBsAg检测中的应用

Application of magnetic beads concentration method in the detection of low concentration of HBsAg

目的:建立一种以磁珠为介质的标本浓缩方法(磁珠浓缩法),提高HBsAg的检测灵敏度和阳性检出率,用于低浓度HBsAg的测定。方法:BCA蛋白检测法检测磁珠吸附前后和洗脱液中HBsAg蛋白含量,判断吸附HBsAg的能力。磁珠浓缩法浓缩HBsAg阳性、HBsAg阴性、已标定HBsAg浓度的血清系列稀释品和低浓度HBsAg的血清标本,比较浓缩前后的S/CO值。结果:在一定的浓度范围内,磁珠吸附HBsAg随着HBsAg浓度的增高而增多,磁珠吸附HBsAg纯品后,10mmol/LNaOH洗脱HBsAg的洗脱率是(71.02±3.24)%。磁珠浓缩后,S/CO值高于浓缩前(P<0.01),不会增加检测HBsAg的非特异性(P>0.05),S/CO值与HBsAg浓度具有良好的线性(r=0.998),最低检测限是0.1IU/mL,对低浓度HBsAg的阳性检出率是80.8%,与浓缩前比较,差异具有统计学意义(χ2=18.513,P<0.01)。结论:磁珠浓缩法可明显提高ELISA检测HBsAg的灵敏度和阳性检出率,具有一定的研究意义。

Objective To establish a method of specimen enrichment based on magnetic beads as medium （magnetic beads concentration method） for improving the detection sensitivity and positive rates of HBsAg and detection of low concentration of HBsAg. Methods The amount of HBsAg protein before, after adsorption and elution was determined by BCA kits, the adsorption ability of HBsAg was judged. Magnetic beads enrichment the positive HBsAg specimen, negative HBsAg specimen, the serum dilution product which have calibrated HBsAg concentration and low concentration HBsAg specimen, compared the S/CO value before and after concentration. Results The quantity of magnetic beads＇ adsorption of HBsAg increased along with the increase of the concentration of HBsAg in a certain concentration range. After adsorption, the adsorbed HBsAg was eluted by 10 mmol/L NaOH, and the elution rate is （71.02 ± 3.24）%. After magnetic beads enrichment, S/CO value is higher than before concentration （P 〈 0.01 ）, and it does not increase the nonspecific detection of HBsAg （P 〉 0.05）, the S/CO value was in good correlation to HBsAg concentration （r = 0.998）, the minimum detection limit was 0.1 IU/mL, the positive detection rate of low HBsAg concentration specimen was 80.8%, it has significant statistical difference between before and after concentration （X^2 = 18.513, P 〈 0.01 ）. Conclusion Magnetic beads can obviously improve the sensitivity and positive rate of ELISA detection of HBsAg, which has some study value.