The efficicancy of Cystatine C as the biomarker for acute kidney injury

Abstract

Acute kidney injury (AKI) is diagnosed by rising serum creatinine (Cr) level (increase rate) and decreasing urine volume. However, as the serum Cr level has a low sensitivity for glomerular filtration rate loss in early stages, biomarkers that diagnose AKI more specifically and earlier, as well as reflect the severity are expected. As a low molecular weight protein (molecular weight is 13.3kDa) which is produced in a constant amount from whole nucleated cells, Cystatin C (Cys-C) is expected to be a biomarker of AKI, since it begins to rise above the reduced renal function in early stages compared with Cr. The most usefulness of Cys-C is being compatible with automatic biochemical analyzer, and possibility to practically apply in clinic. AKI is affected by complex factors such as damaged parts of the kidney or time elapsed since the damage occurred. Thus, not only Cys-C but various combinations of biomarkers are required, and the establishment of new biomarkers is urgently needed.