Biomarkers for acute kidney injury

Acute kidney injury (AKI) is associated with both a number of adverse outcomes and with morbidity and mortality. Therefore, early diagnosis of AKI is very important. Several novel AKI biomarkers have been found and studied. Markers include impaired filtration barriers, reduced tubular reabsorption, increased release of tubular proteins due to cell damage and/or activation of inflammatory cells, and the release of activation products in response to injury. Neutrophil gelatinase–associated lipocalin, kidney injury molecule 1, interleukin-18, liver-type fatty acid-binding protein, cystatin C, tissue inhibitor of metalloproteinase-2, and insulin-like growth factor-binding protein 7 markers appear to be useful; however, the clinical uses of AKI biomarkers are not yet well defined and the number of clinical trials is limited. Additionally, analytical validation of tests for AKI markers is also required. Therefore, measurement of the daily quantity of urine and determination of blood urea and creatinine levels are most often used for both diagnosis and classification of AKI in clinical practice.