The Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) group developed a β2M-based GFR estimating equation in a cohort of 2,380 patients primarily comprised of Caucasians and African Americans with a mean measured GFR (mGFR), serum Cr, and serum β2M levels of 47.5 (±21.7) ml/min/1.73 m2, 1.9 (±0.9) mg/dl, and 4.3 (±2.4) mg/l, respectively (39). This evidence concerns the gene B2M and chronic kidney disease.