Diagnostic and Prognostic Stratification in the Emergency Department Using Urinary Biomarkers of Nephron Damage: A Multicenter Prospective Cohort Study

Study Questions:

Are urinary biomarkers of nephron damage predictive of outcomes in patients admitted via the emergency department (ED)?


Five urinary biomarkers (urinary neutrophil gelatinase–associated lipocalin, kidney injury molecule 1, urinary liver-type fatty acid binding protein, urinary interleukin-18, and cystatin C) were measured in 1,635 ED patients at the time of hospital admission. The association of the biomarkers with intrinsic acute kidney injury (AKI) and adverse outcomes during hospitalization was determined.


All biomarkers were elevated in intrinsic AKI, but urinary neutrophil gelatinase–associated lipocalin was most useful (81% specificity, 68% sensitivity at a 104 ng/ml cutoff) and predictive of AKI severity. Intrinsic AKI was strongly associated with adverse in-hospital outcomes. Urinary neutrophil gelatinase–associated lipocalin and urinary kidney injury molecule 1 predicted a composite outcome of dialysis initiation or death during hospitalization, and both improved the net risk classification compared with conventional assessments.


The authors concluded that urinary biomarkers of nephron damage enable prospective diagnostic and prognostic stratification in the ED.


Renal dysfunction portends poor prognosis in hospitalized patients. Serum creatinine is useful as a measure of renal function; however, levels are affected by many factors including muscle mass, age, medications, nutritional status, and altered hemodynamics. More specific and thus informative biomarkers of renal injury may provide additional prognostic information and may be useful in guiding potential preventive therapies. This study demonstrates that certain biomarkers of nephron damage may be useful in the assessment of patients admitted to the hospital, even in the setting of low serum creatinine.

Clinical Topics: Dyslipidemia, Lipid Metabolism

Keywords: Lipocalins, Prognosis, Fatty Acid-Binding Proteins, Interleukin-18, Biological Markers, Acute Kidney Injury, Hospitalization, Cystatin C

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