title: A new screening method for proteinuria using Erythrosin B and an automated analyzer--rapid, sensitive and inexpensive determination.
abstract: BACKGROUND
  In spite of the urgent necessity for a screening test of urinary protein for the early diagnosis of kidney diseases, a rapid, accurate and cost-effective method for their detection has yet to be developed.
  
  
  METHODS
  A solution containing a buffer agent (pH 2.3) and surfactants and a solution of Erythrosin B are added to a urine sample. After letting the mixture stand for 5 min at 37°C, the dye-bound protein is measured by a spectrophotometer at 546 nm using a Hitachi 7170S automated analyzer.
  
  
  RESULTS
  The calibration curve was linear with human serum albumin concentration in the range of 2.4-200 mg/l. The detection limit, 2.4 mg/l was superior to conventional dye-binding methods by one order of magnitude and comparable to the turbidimetric immunoassay (TIA). Spot urine samples from 70 patients who showed (-) or (±) in the dip-stick screening test for proteinuria and 79 healthy volunteers were analyzed. There was an excellent correlation (r=0.978, n=149) between the results given by the proposed method and those by the TIA.
  
  
  CONCLUSIONS
  This method provides a viable alternative to the conventional immunoassay-based methods for urinary protein measurement, and will be useful in the diagnosis of early stage kidney disease.
authors.affiliation: Division of Nephrology, Department of Internal Medicine, Juntendo University Faculty of Medicine, Tokyo, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Horikoshi
authors.forename: Asami
authors.initials: A
authors.lastname: Higurashi
authors.forename: Emiko
authors.initials: E
authors.lastname: Kaneko
authors.forename: Hajime
authors.initials: H
authors.lastname: Yoshimura
authors.forename: Isao
authors.initials: I
authors.lastname: Ohsawa
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Suzuki
authors.forename: Chieko
authors.initials: C
authors.lastname: Hamada
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Tomino
mesh_terms: D001322:Autoanalysis / Q000191:economics* / Q000379:methods*; D001331:Automation / Q000191:economics / Q000379:methods; D002138:Calibration; D004923:Erythrosine / Q000737:chemistry*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007118:Immunoassay; D011507:Proteinuria / Q000175:diagnosis* / Q000652:urine*; D012680:Sensitivity and Specificity
chemical_list: D004923:Erythrosine