Creatinine Clearance
The Test
How is it used?
In patients with known chronic kidney disease or congestive heart failure (which decreases the rate of blood flow), the creatinine clearance test may be ordered to help monitor the progress of the disease and evaluate its severity. It may also be used to help determine if and when kidney dialysis may be necessary.
When is it ordered?
Signs and symptoms that may be an indication of kidney problems include:
- Swelling or puffiness, particularly around the eyes or in the face, wrists, abdomen, thighs, or ankles
- Urine that is foamy, bloody, or coffee-colored
- A decrease in the amount of urine
- Problems urinating, such as a burning feeling or abnormal discharge during urination, or a change in the frequency of urination, especially at night
- Mid-back pain (flank), below the ribs, near where the kidneys are located
- High blood pressure (hypertension)
- Blood and/or protein in the urine
It may also be ordered periodically when it is known that a patient has a kidney disorder or decreased blood flow to the kidneys due to a condition such as congestive heart failure.
What does the test result mean?
A decreased creatinine clearance rate may also occur when there is decreased blood flow to the kidneys as may occur with congestive heart failure, obstruction within the kidney, or acute or chronic kidney failure. The less effective the kidney filtration, the greater the decrease in clearance.
Increased creatinine clearance rates may occasionally be seen during pregnancy, exercise, and with diets high in meat, although this test is not typically used to monitor these conditions.
Is there anything else I should know?
Creatinine clearance rates tend to fall later in life as the glomerular filtration rate (GFR - the rate at which the glomeruli filter the blood) declines.
Certain drugs, such as aminoglycosides, cimetidine, cisplatin, and cephalosporins, can decrease the creatinine clearance measurement. Diuretics can increase the result.
