%0 Journal Article
%T Albumin adsorption onto surfaces of urine collection and analysis containers.
%A Robinson MK
%A Caudill SP
%A Koch DD
%A Ritchie J
%A Hortin G
%A Eckfeldt JH
%A Sandberg S
%A Williams D
%A Myers G
%A Miller WG
%J Clin Chim Acta
%V 431
%N 0
%D Apr 2014 20
%M 24513540
%F 6.314
%R 10.1016/j.cca.2014.01.035
%X <B>BACKGROUND: </B>Adsorption of albumin onto urine collection and analysis containers may cause falsely low concentrations.<BR><B>METHODS: </B>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.<BR><B>RESULTS: </B>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.<BR><B>CONCLUSIONS: </B>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.