Question: how are gfr and creatinine clearance related?
Answer: Creatinine clearance ( CrCl ) is an estimate of Glomerular Filtration Rate ( GFR ); however, CrCl is slightly higher than true GFR because creatinine is secreted by the proximal tubule (in addition to being filtered by the glomerulus). The additional proximal tubule secretion falsely elevates the CrCl estimate of GFR .