Creatinine Products | Cleanchem - Creatinine is a metabolic byproduct of creatine phosphate in muscle and is commonly used as a biomarker of kidney function. Blood and urine levels of creatinine help assess glomerular filtration rate (GFR) and overall renal health. Elevated creatinine levels can indicate kidney dysfunction or dehydration. It is not used as a drug but plays a vital diagnostic role in clinical practice.