title: Measurement of the modification and interference rate of urinary albumin detected by size-exclusion HPLC.
abstract: The measurement of the excretion of urinary albumin (albuminuria) is an important and well-established method to assess clinical outcomes. A high-performance liquid chromatography (HPLC) method has been introduced to measure albuminuria. Using this method, it was found that commonly used immunological methods do not measure a fraction of urinary albumin. Some authors presumed that the reason of immuno-unreactivity is the modification of urinary albumin; some others presumed that the difference is merely because of interference. In order to decide this question, we established an HPLC method equipped with tandem UV and fluorescent detection to assess the changes in the detectability of albumin with the rate of modification. For this measurement, differently modified forms of albumin were used. Urine samples of diabetic patients were also measured to find a potential connection between the modification rate and clinical parameters. Secondly, we have established a reversed phase HPLC method to assess the interference rate. We conclude that albumin modification does not affect immunoreactivity. The modification rate of urinary albumin in diabetic patients showed a correlation with renal function. The interference rate of the albumin peak was found to be 12.7% on average, which does not explain the difference between the two methods.
authors.affiliation: 2nd Department of Medicine and Nephrological Center, Faculty of Medicine, University of Pécs, Pécs, Hungary.
authors.forename: Lajos
authors.initials: L
authors.lastname: Markó
authors.forename: Gergo Attila
authors.initials: GA
authors.lastname: Molnár
authors.forename: Zoltán
authors.initials: Z
authors.lastname: Wagner
authors.forename: Katalin
authors.initials: K
authors.lastname: Böddi
authors.forename: Tamás
authors.initials: T
authors.lastname: Koszegi
authors.forename: Zoltán
authors.initials: Z
authors.lastname: Szabó
authors.forename: Zoltán
authors.initials: Z
authors.lastname: Matus
authors.forename: István
authors.initials: I
authors.lastname: Szijártó
authors.forename: Akos
authors.initials: A
authors.lastname: Mérei
authors.forename: Géza
authors.initials: G
authors.lastname: Nagy
authors.forename: István
authors.initials: I
authors.lastname: Wittmann
mesh_terms: D000419:Albuminuria / Q000175:diagnosis / Q000652:urine*; D002850:Chromatography, Gel / Q000379:methods*; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D003920:Diabetes Mellitus / Q000175:diagnosis / Q000652:urine; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012709:Serum Albumin / Q000032:analysis*; D016482:Urinalysis / Q000379:methods
chemical_list: D012709:Serum Albumin