METHODS: We added (125)I-labeled human serum albumin to urine and to phosphate buffered solutions, incubated them with 22 plastic container materials and measured adsorption by liquid scintillation counting.
RESULTS: Adsorption of urine albumin (UA) at 5-6 mg/l was <0.9%; and at 90 mg/l was <0.4%. Adsorption was generally less at pH8 than pH5 but only 3 cases had p<0.05. Adsorption from 11 unaltered urine samples with albumin 5-333 mg/l was <0.8%. Albumin adsorption for the material with greatest binding was extrapolated to the surface areas of 100 ml and 2l collection containers, and to instrument sample cups and showed <1% change in concentration at 5 mg/l and <0.5% change at 20 mg/l or higher concentrations. Adsorption of albumin from phosphate buffered solutions (2-28%) was larger than that from urine.
CONCLUSIONS: Albumin adsorption differed among urine samples and plastic materials, but the total influence of adsorption was <1% for all materials and urine samples tested. Adsorption of albumin from phosphate buffered solutions was larger than that from urine and could be a limitation for preparations used as calibrators.
方法:我们将(125)I标记的人血清白蛋白添加到尿液和磷酸盐缓冲溶液中,将它们与22个塑料容器材料一起孵育,并通过液体闪烁计数来测量吸附。
结果:在5-6mg/l时,尿白蛋白(UA)的吸附率<0.9%;在90mg/l时<0.4%。在pH8时的吸附通常小于pH5,但只有3例具有p<0.05。用白蛋白5-333mg/l从11个未改变的尿液样品中吸附<0.8%。将具有最大结合的材料的白蛋白吸附外推至100毫升和2升收集容器的表面积,和仪器样品杯,并显示<1%的变化在5毫克/升和<0.5%的变化在20毫克/升或更高的浓度。磷酸盐缓冲溶液中白蛋白的吸附量(2-28%)大于尿液中白蛋白的吸附量。
结论:白蛋白吸附在尿样和塑料材料之间存在差异,但是对于所有测试的材料和尿液样品,吸附的总影响<1%。白蛋白从磷酸盐缓冲溶液中的吸附量大于从尿液中的吸附量,这可能是用作校准品的制剂的限制。