Creatinine is a nitrogenous waste product formed in muscle from creatine phosphate. Endogenous production of creatinine is proportional to muscle mass and body weight.
Causes of Increased Serum Creatinine Level | Causes of Decreased Serum Creatinine Level |
1. Pre-renal, renal, and post-renal azotemia 2. Large amount of dietary meat 3. Active acromegaly and gigantism |
1. Pregnancy 2. Increasing age (reduction in muscle mass) |
GFR is measured to (i) detect suspected incipient kidney disease (i.e. early detection), (ii)monitor the course of established kidney disease, (iii) plan renal replacement therapy in advanced renal disease, and (iv) adjust the dosage of certain drugs which are nephrotoxic.
BUN/creatinine ratio is to discriminate pre-renal and post-renal azotemia from renal azotemia.