Specific, sensitive and accurate quantification of albumin, retinol binding protein and transferrin in human urine and serum by zone immunoelectrophoresis assay (ZIA).
For zone immunoelectrophoresis assay (ZIA) glass tubes, ID 2 mm and 90 mm high, are filled to 2/3 with buffer containing agarose and antibodies against the protein to be quantified, each sample being pipetted on top of separate agarose gel rods. On electrophoresis at 35-150 V for several hours, the sample proteins enter the gel with resultant immunoprecipitates, visualized by staining. The extension of each immunoprecipitation zone from the upper gel surface (measured with a ruler) is directly proportional to the amount of protein in each sample and can easily be quantitated by comparison with a linear calibration curve. ZIA can be used for quantification of several proteins in blood serum and plasma as well as in urine, as is illustrated for albumin, retinol-binding protein (RBP) and transferrin. The recovery of the pure proteins added to urine is often close to 100%. ZIA has many advantages: (i) simple apparatus and procedure (no gel punching nor cooling), (ii) minimal antiserum consumption (1 mL may allow > 1000 assays), (iii) electrophoresis can be performed within a few hours or overnight, (iv) low coefficient of variation (often < 4%), (v) linear calibration curves, (vi) low detection limit (< 20 ng/mL), (vii) wide concentration ranges, (viii) no kits nor unique antisera preparation are required, and (ix) good agreement with the results from other methods.
Vesterberg
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National Institute of Occupational Health, Solna, Sweden.
D000419:Albuminuria / Q000652:urine*; D006801:Humans; D007122:Immunoelectrophoresis / Q000379:methods*; D008297:Male; D015203:Reproducibility of Results; D012177:Retinol-Binding Proteins / Q000032:analysis* / Q000652:urine; D054839:Retinol-Binding Proteins, Plasma; D012680:Sensitivity and Specificity; D012709:Serum Albumin / Q000032:analysis*; D014168:Transferrin / Q000032:analysis* / Q000652:urine
D012177:Retinol-Binding Proteins; D054839:Retinol-Binding Proteins, Plasma; D012709:Serum Albumin; D014168:Transferrin