title: Clinical utility of urinary liver-type fatty acid binding protein measured by latex-enhanced turbidimetric immunoassay in chronic kidney disease.
abstract: BACKGROUND
  Urinary liver-type fatty acid binding protein (L-FABP) measured by enzyme-linked immunosorbent assay method (ELISA) was approved as a clinical biomarker of tubular damage by the Japanese Ministry of Health, Labor and Welfare (MHLW) in 2011. We evaluated a new latex-enhanced immunoturbidimetric assay (LTIA) to evaluate the clinical utility of urinary L-FABP measured by LTIA versus an ELISA assay.
  
  
  METHODS
  LTIA with anti-human L-FABP mouse monoclonal antibodies was performed using an automated clinical chemistry analyzer. Five positive samples with low, medium and high L-FABP concentrations were analyzed to determine the within-run precision. In patients with chronic kidney disease (CKD) (n=91), urinary L-FABP levels were measured by ELISA and LTIA.
  
  
  RESULTS
  Measurement of urinary L-FABP revealed urinary L-FABP levels within 30 min. The within-run coefficient of variation was 10.0% for 1.4 ng/mL, 4.4% for 2.5 ng/mL, 3.2% for 9.8 ng/mL, 1.5% for 50.1 ng/mL, and 1.2% for 102.7 ng/mL. Concentrations of urinary L-FABP measured by LTIA were significantly correlated with those measured by ELISA (ρ=0.932). Proportional systematic error was almost within limits of agreement (LOA). Urinary L-FABP levels measured by LTIA were significantly correlated with urinary albumin (ρ=0.634), urinary NAG (ρ=0.688) and eGFR (ρ=-0.561).
  
  
  CONCLUSIONS
  Measurement of urinary L-FABP by LITA was simple, speedy, and similar in quality to ELISA results. Therefore, this method was approved as external body diagnosing medicines by the Japanese MHLW in 2014. Urinary L-FABP is expected to be widely used in various pathophysiological conditions by measuring urinary L-FABP using LTIA.
authors.forename: Atsuko
authors.initials: A
authors.lastname: Kamijo-Ikemori
authors.forename: Takeshi
authors.initials: T
authors.lastname: Sugaya
authors.forename: Maki
authors.initials: M
authors.lastname: Yoshida
authors.forename: Seiko
authors.initials: S
authors.lastname: Hoshino
authors.forename: Satoshi
authors.initials: S
authors.lastname: Akatsu
authors.forename: Satoshi
authors.initials: S
authors.lastname: Yamazaki
authors.forename: Kenjiro
authors.initials: K
authors.lastname: Kimura
authors.forename: Yugo
authors.initials: Y
authors.lastname: Shibagaki
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D015415:Biomarkers / Q000097:blood / Q000652:urine*; D003430:Cross-Sectional Studies; D004797:Enzyme-Linked Immunosorbent Assay; D050556:Fatty Acid-Binding Proteins / Q000652:urine*; D005260:Female; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D007840:Latex / Q000737:chemistry*; D008297:Male; D051379:Mice; D008875:Middle Aged; D009391:Nephelometry and Turbidimetry / Q000379:methods*; D051436:Renal Insufficiency, Chronic / Q000175:diagnosis* / Q000652:urine*; D055815:Young Adult
chemical_list: D015415:Biomarkers; C493319:FABP1 protein, human; D050556:Fatty Acid-Binding Proteins; D007840:Latex