Low-Molecular Weight Proteins as Markers for Glomerular Filtration Rate

Abstract
Inulin clearance (CIn) is the usual gold standard for evaluating glomerular filtration rate (GFR), but technical difficulties and patient inconvenience prevent its widespread use (1). The most commonly used marker for GFR is serum creatinine, but muscle wasting and tubular secretion may lead to overestimation of GFR (2)(3). Serum concentrations of the low-molecular weight proteins cystatin C (CysC) (4), β2-microglobulin (B2M) (5)(6), and β-trace protein (BTP) (7) maybe useful alternatives for detecting reduced GFR, but no study to date has compared all of these proteins directly to CIn.