title: Evaluation of a particle enhanced turbidimetric assay for the measurement of neutrophil gelatinase-associated lipocalin in plasma and urine on Architect-8000: Analytical performance and establishment of reference values.
abstract: OBJECTIVE
  Neutrophil gelatinase-associated lipocalin (NGAL) is a promising biomarker for acute kidney injury. NGAL can be measured in both blood and urine. Apart from kidney injury, NGAL levels in both plasma and urine can be influenced by various pathological situations. Accurate evaluation and comparison of results deriving from clinical studies require robust assays, appropriate specimen handling and reference intervals that will reflect its levels in a healthy population for both biological matrices.
  
  
  METHODS
  We report the analytical validation of a latex particle-enhanced turbidimetric immunoassay (PETIA) aimed to measure NGAL in plasma and urine on an automated biochemistry analyzer (ABBOTT-Architect-8000). Assay performance characteristics were evaluated using standard protocols. Urine and plasma specimen storage requirements were determined and reference ranges for blood and urine were determined using healthy controls.
  
  
  RESULTS
  The assay is precise (total CV%<4.8%), and sensitive (limit of quantification: 8.4 ng/mL for plasma and 9.0 ng/mL for urine), showing no hook effect. Calibration is stable for at least 30 days. The assay showed excellent linearity over the studied interval (20-4450 ng/mL). The analyte is stable at 4 °C for at least 5 days, and at 20 °C for 4h. Gender specific reference ranges for plasma (male: 38.7-157.6 ng/mL, female: 24.4-142.5 ng/mL) and unisex for urine (<9.0-49.41 ng/mL) are proposed.
  
  
  CONCLUSIONS
  Our data indicate that NGAL can be measured with adequate precision and sensitivity on automated biochemistry analyzers and its measurement could easily be added to a standard panel to screen kidney diseases.
authors: Clinical Biochemistry Department, KAT General Hospital, Kifissia, Greece. Electronic address: kostas.makris.km@gmail.com.
authors: Konstantinos
authors: K
authors: Makris
authors: Internal Medicine Department, KAT General Hospital, Kifissia, Greece.
authors: Dimitra
authors: D
authors: Stefani
authors: Department of Clinical Biochemistry, Medical School, Attikon University Hospital, University of Athens, Greece.
authors: Eleni
authors: E
authors: Makri
authors: Blood Transfusion Center, KAT General Hospital, Kifissia, Greece.
authors: Ioannis
authors: I
authors: Panagou
authors: Department of Clinical Biochemistry, Medical School, Attikon University Hospital, University of Athens, Greece.
authors: Maria
authors: M
authors: Lagiou
authors: Department of Clinical Biochemistry, Medical School, Attikon University Hospital, University of Athens, Greece.
authors: Antonia
authors: A
authors: Sarli
authors: Internal Medicine Department, KAT General Hospital, Kifissia, Greece.
authors: Moysis
authors: M
authors: Lelekis
authors: Department of Clinical Biochemistry, Medical School, Attikon University Hospital, University of Athens, Greece.
authors: Christos
authors: C
authors: Kroupis
mesh_terms: D000209:Acute-Phase Proteins / Q000235:genetics / Q000652:urine*; D000293:Adolescent; D000328:Adult; D000368:Aged; D057205:Automation, Laboratory; D015415:Biomarkers / Q000097:blood / Q000652:urine; D002138:Calibration; D005260:Female; D015870:Gene Expression; D064368:Healthy Volunteers; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D057230:Limit of Detection; D000071068:Lipocalin-2; D054834:Lipocalins / Q000097:blood* / Q000235:genetics / Q000652:urine*; D008297:Male; D008875:Middle Aged; D009391:Nephelometry and Turbidimetry / Q000379:methods*; D011518:Proto-Oncogene Proteins / Q000097:blood* / Q000235:genetics / Q000652:urine*; D012016:Reference Values; D012737:Sex Factors; D013048:Specimen Handling / Q000592:standards
chemical_list: D000209:Acute-Phase Proteins; D015415:Biomarkers; C489506:LCN2 protein, human; D000071068:Lipocalin-2; D054834:Lipocalins; D011518:Proto-Oncogene Proteins
keywords: Acute kidney injury; Method evaluation; Neutrophil gelatinase-associated lipocalin; Particle enhanced turbidimetric assay; Reference interval