Creatinine and creatinine clearance tests measure creatinine levels in your blood and urine. These tests give information about how well your kidneys are working. The creatinine clearance value is found from the amounts of creatinine in the urine and blood and from the amount of urine you pass in 24 hours.hild: 0.3-0.7 mg/dL. Creatinine clearance: Men (younger than age 40): 107-139 milliliters per minute (mL/min) or 1.8-2.3 milliliters per second (mL/sec). Women (younger than age 40): 87-107 mL/min or 1.5-1.8 mL/sec. Creatinine clearance values normally go down as you get older.