title: Insights on urinary NGAL obtained in a primary care setting.
abstract: BACKGROUND
  A majority of patients developing acute kidney injury (AKI) receive medical care from their primary care physicians prior to the occurrence of conditions that predispose them to this complication.
  
  
  METHODS
  To characterize the uNGAL concentrations in primary care patients and to assess these concentrations with regard to different reference intervals, we conducted a multicenter, cross-sectional study with random selection of general practitioners (GP) from all GP offices in seven Swiss cantons. 1000 adults (566 females; mean age 57±17 years) were included.
  
  
  RESULTS
  The median absolute uNGAL was 21 ng/L. Elevated uNGAL (>100 ng/L) together with normal kidney test results (eGFR and albuminuria) were found in 6.5% of all patients. Females had a significantly higher uNGAL than did males. Among a multitude of different clinical and laboratory variables, only age, gender, liver function parameters, WBC and CRP were significantly associated with uNGAL levels in a multivariate analysis. When examining the proposed KDIGO classification of chronic kidney disease, the uNGAL levels at the given eGFR stages changed with increasing albuminuria stages and vice versa.
  
  
  CONCLUSIONS
  Age, gender, markers of inflammation and liver function, exert influences on uNGAL concentrations. A substantial proportion of patients exhibited normal kidney testing together with elevated uNGAL, potentially identifying patients with increased renal stress and at increased risk for the development of AKI.
authors.affiliation: Institute of Social and Preventive Medicine, Medical Economics, University of Zurich, Zurich, Switzerland.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Tomonaga
authors.forename: Thomas
authors.initials: T
authors.lastname: Szucs
authors.forename: Patrice
authors.initials: P
authors.lastname: Ambühl
authors.forename: Stefan
authors.initials: S
authors.lastname: Nock
authors.forename: Martin
authors.initials: M
authors.lastname: Risch
authors.forename: Lorenz
authors.initials: L
authors.lastname: Risch
mesh_terms: D000209:Acute-Phase Proteins / Q000652:urine*; D000368:Aged; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D000071068:Lipocalin-2; D054834:Lipocalins / Q000652:urine*; D008297:Male; D008875:Middle Aged; D011320:Primary Health Care / Q000458:organization & administration*; D011518:Proto-Oncogene Proteins / Q000652:urine*
chemical_list: D000209:Acute-Phase Proteins; C489506:LCN2 protein, human; D000071068:Lipocalin-2; D054834:Lipocalins; D011518:Proto-Oncogene Proteins