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The creatinine clearance test compares the level of creatinine in urine with the creatinine level in the blood. (Creatinine is a breakdown product of creatine, which is an important part of muscle.) The test helps provide information on kidney function.
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How the test is performedThis test requires both a blood and urine sample. You will collect your urine for 24 hours, and then have blood taken.
- For information on giving a blood sample, see: venipuncture.
- For information on how to collect the urine sample, see: 24-hour urine collection.
The samples are sent to a laboratory. The laboratory specialist measures the level of creatinine in both the urine and blood samples, and looks at how much urine you collected in 24 hours.
The clearance rate is then calculated. The calculation is adjusted for your specific body size.
The creatinine clearance appears to decrease with age (each decade corresponds to a decrease of about 6.5 ml/min./1.73 m2).
How to prepare for the testIf the collection is being taken from an infant, a couple of extra collection bags may be necessary.
How the test will feelThe urine test involves only normal urination and there is no discomfort. When the needle is inserted to draw blood, some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing.
Why the test is performedThe creatinine clearance test is used to estimate the glomerular filtration rate (GFR).
However, because a small amount of creatinine is released by the filtering tubes in the kidneys, creatinine clearance is not exactly thto the same as the GFR. In fact, creatinine clearance usually overestimates the GFR. This is particularly true in patients with advanced kidney failure.
Normal ValuesClearance is often measured as milliliters/minute (ml/min). Normal values are:
- Male: 97 to 137 ml/min.
- Female: 88 to 128 ml/min.
Note: Normal values ranges may vary slightly among different laboratories.
What abnormal results meanAbnormal results (lower-than-normal creatinine clearance) may indicate:
- Acute tubular necrosis
- Bladder outlet obstruction
- Congestive heart failure
- Dehydration
- Glomerulonephritis
- Renal ischemia (blood deficiency
- Renal outflow obstruction (usually must affect both kidneys to reduce the creatinine clearance)
- Shock
- Acute renal failure
- Chronic renal failure
- End-stage renal disease
The risks of the test are minimal and are related to the blood draw process. Rarely, the following will occur:
- Excessive bleeding at blood draw site
- Fainting or feeling light-headed
- Hematoma (blood accumulating under the skin)
- Infection (a slight risk any time the skin is broken)
- Multiple punctures to locate veins
Factors that may interfere with the accuracy of the test are as follows:
- Incomplete urine collection
- Pregnancy
- Vigorous exercise
Drugs that can interfere with creatinine clearance measurements include: cimetidine, trimethoprim, and drugs that can damage the kidneys, such as cephalosporins.
The creatinine clearance test should only be done for patients who are medically stable. Such patients may have a rapidly changing creatinine clearance, and therefore any result may be inaccurate.
ReferencesBazari H. Approach to the patient with renal disease. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 115.
What else can I help you with?
What should the creatinine level be for dialysis?
Creatinine clearance is a measure of kidney function. Patients are on dialysis because their kidneys do not function properly thus their creatinine clearance would be very, very low. Some patients may have some residual kidney function but their creatinine clearance would be less than probably 10 ml/min.
What is the creatinine clearance test?
The creatinine clearance test measures how well the kidneys are filtering waste products from the blood. It involves collecting urine samples over a period of time to determine the amount of creatinine excreted. This test is used to assess kidney function and detect any abnormalities.
What is creatinine clearance?
In general, creatinine clearance is the removal of creatinine from the body. In renal physiology, creatinine clearance is the volume of blood plasma that is cleared of creatinine per unit time. Clinically, creatinine clearance is a useful measure for estimating the glomerular filtration rate (GFR) of the kidneys.1Creatinine is a breakdown product of creatine phosphate in muscle, and is usually produced at a fairly constant rate by the body (depending on muscle mass).2The result of this test is an important gauge used in assessing excretory function of the kidneys.11. http://en.wikipedia.org/wiki/Creatinine_clearance2. http://en.wikipedia.org/wiki/Creatinine
Difference between clearance and creatinine clearance?
Clearance is the volume of blood cleared of a substance per unit of time, usually measured in milliliters per minute. Creatinine clearance specifically refers to the rate at which the kidneys remove creatinine from the blood, serving as an indicator of renal function. It is a valuable measurement in assessing kidney health.
What do low clearance values for creatinine indicate?
Low clearance values for creatinine and urea indicate a diminished ability of the kidneys to filter these waste products from the blood and to excrete them in the urine.
What is the significance of creatinine clearance?
to find out kidney filteration rate.
What is the gfr of patient with urine creatnint clearance of 30?
The glomerular filtration rate (GFR) cannot be directly calculated from urine creatinine clearance. However, assuming a constant relationship between GFR and creatinine clearance, a urine creatinine clearance of 30mL/min may correspond to a GFR of approximately 30mL/min. Further evaluation by a healthcare provider is recommended.
What is creatinine coeficient?
Creatinine clearance is a measure of the kidney's ability to filter waste products, like creatinine, from the blood. It is calculated using a formula that takes into account a person's age, weight, and gender. The creatinine clearance value helps healthcare providers assess kidney function and determine appropriate treatments.
How do you increase creatinine clearance?
To increase creatinine clearance, you can stay well hydrated by drinking plenty of water, maintain a healthy blood pressure, and follow a balanced diet rich in fruits, vegetables, and lean proteins. Additionally, regular exercise and avoiding certain medications that can affect kidney function may help improve creatinine clearance.
What is the normal creatinine clearance level during pregnancy?
Normal creatinine clearance in most people is over 60 mL/min, however, in pregnancy it is increased by as much as 50% because of increased GFR and renal plasma flow.
What characteristics does an abnormal kidney function test have?
Low clearance values for creatinine and urea indicate diminished ability of the kidneys to filter these waste products from the blood and excrete them in the urine. As clearance levels decrease, blood levels of creatinine and.
What does raised creatinine clearance mean?
Creatinine and creatinine clearance tests measure creatinine levels (the level of the waste product) in your blood and urine to give information about how well your kidneys are working. The substance creatine is formed when food is changed into energy through a process called metabolism. Creatine is broken down into another substance called creatinine, which is taken out of your blood by the kidneys and then passed out of your body in urine. Creatinine is made at a steady rate and is not affected by diet or by normal physical activities. If your kidneys are damaged and cannot work normally, the amount of creatinine in your urine goes down while its level in your blood goes up. 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.
