Creatinine and Creatinine Clearance
How It Feels
The blood sample is taken from a vein in your arm. An elastic band is wrapped around your upper arm. It may feel tight. You may feel nothing at all from the needle, or you may feel a quick sting or pinch.
There is no pain while collecting a 24-hour urine sample.
Risks of a blood test
There is very little chance of a problem from having a blood sample taken from a vein.
- You may get a small bruise at the site. You can lower the chance of bruising by keeping pressure on the site for several minutes.
- In rare cases, the vein may become swollen after the blood sample is taken. This problem is called phlebitis. A warm compress can be used several times a day to treat this.
- Ongoing bleeding can be a problem for people with bleeding disorders. Aspirin, warfarin (Coumadin), and other blood-thinning medicines can make bleeding more likely. If you have bleeding or clotting problems, or if you take blood-thinning medicine, tell your doctor before your blood sample is taken.
There is no chance for problems while collecting a 24-hour urine sample.
Creatinine and creatinine clearance tests measure creatinine levels in your blood and urine to 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. This value is the amount of blood cleared of creatinine per minute, based on your body size.
The normal values listed here—called a reference range—are just a guide. These ranges vary from lab to lab, and your lab may have a different range for what's normal. Your lab report should contain the range your lab uses. Also, your doctor will evaluate your results based on your health and other factors. This means that a value that falls outside the normal values listed here may still be normal for you or your lab.
Blood creatinine and creatinine clearance
Men: 0.6–1.2 milligrams per deciliter (mg/dL) or 53–106 micromoles per liter (mcmol/L)
Women: 0.5–1.1 mg/dL or 44–97 mcmol/L
Teen: 0.5–1.0 mg/dL
Child: 0.3–0.7 mg/dL
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 (normal values go down by 6.5 mL/min for every 10 years past the age of 20).