Established and emerging markers of kidney function.
BACKGROUND
The kidney performs a multitude of essential functions to maintain homeostasis. In clinical medicine, glomerular filtration rate (GFR) provides the best index of overall kidney function, and proteinuria adds additional information on renal and nonrenal prognosis. Several novel biomarkers of kidney injury and function are under investigation.


BACKGROUND
Plasma creatinine concentration is the most widely used measure for estimation of GFR. Plasma cystatin C and β-trace protein may eventually prove to be superior to creatinine. GFR may be measured directly by use of exogenous filtration markers, although their role is primarily limited to the research setting. Real-time, noninvasive measurement of GFR by using fluorescently labeled markers may be available in the future. Novel biomarkers of tubular injury such as neutrophil gelatinase-associated lipocalin, kidney injury molecule-1, liver-type fatty acid binding protein, N-acetyl-β-(D)-glucosaminidase, and interleukin-18 may enable the early detection of acute kidney injury before or in the absence of a change in GFR.


CONCLUSIONS
A variety of methods are available to assist clinicians in the assessment of kidney function and injury. Ongoing investigation will help determine the utility of several new markers and clarify their role in the care of patients with and at risk for kidney disease.
Division of Nephrology, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA.
Michael A
MA
Ferguson
Sushrut S
SS
Waikar
D058186:Acute Kidney Injury / Q000175:diagnosis; D015415:Biomarkers / Q000097:blood / Q000652:urine; D003952:Diagnostic Imaging / Q000379:methods; D005919:Glomerular Filtration Rate; D006801:Humans; D007668:Kidney / Q000473:pathology / Q000503:physiopathology; D007677:Kidney Function Tests; D011507:Proteinuria / Q000175:diagnosis; D051436:Renal Insufficiency, Chronic / Q000175:diagnosis
D015415:Biomarkers