Biochemical Markers of Renal Function

Kidney damage can be induced by ischemia, autoimmune diseases, hypertension, allograft rejection, metabolic or genetic disorders, infections or toxins. The influence of these factors could result in acute kidney injury (AKI) defined as an unexpected decrease in urine output or renal function, or encourage the development of chronic kidney disease (CKD). Biomarkers of renal function, measured in urine and serum, are in increasing use in order to estimate the severity and nature of kidney injury, and consequently apply appropriate therapy and improve patient management. The determined values of biomarkers can suggest the potential risk of kidney disease and the type of renal injury, predict the disease progression, as well as be helpful for assessing the response to an applied therapy. Although novel biomarkers are in practical use, serum creatinine, the indicator of glomerular filtration rate is still the most frequently used biomarker of renal function despite its known limitations. In recent decades, numerous studies resulted in discovering urinary and serum proteins that can serve as biomarkers for early and accurate detection of AKI and its development, as well as the identification of CKD. This review gives an overview of the most important renal biomarkers investigated in kidney diseases, classified in following types: functional biomarkers, up-regulated proteins, enzymes, and cycle arrest biomarkers. It describes their properties, physiological roles, and discusses the utility of these molecules in different clinical settings.