Creatinine Clearance

Creatinine is formed when creatine is broken down by the body; the levels of creatinine produced by the body are dependent on muscle mass (those with higher muscle mass have higher levels of creatinine in their bloodstream). Creatinine is removed from the body by the kidneys, as blood passes through them.

When is the test used?

The creatinine clearance test is used to assess the function of the kidneys; the test measures the filtration capabilities of the kidneys. The test is used to detect problems with kidney function and will usually be ordered by a doctor when they suspect that there is a problem with the patient’s kidneys. The test may also be ordered if the patient has a health problem, which may affect kidney function; this may be the case if the patient has congestive heart failure or diabetes.

How is the test performed?

The test is done by collecting and analysing a sample of blood and collecting a 24 hour urine sample. The blood sample is obtained by inserting a needle into a vein in the arm; the blood is collected in a syringe, placed in a bottle, labelled and sent away to the laboratory for analysis. The urine sample must be collected over a 24 hour period; the results of the tests will then be analysed together.

What do the test results mean?

The test results give an idea of kidney function by measuring the rate of filtration; creatinine clearance should be approximately 100mL/minute. If the rate is lower than this, it may indicate that there is a problem with the kidneys and some function has been lost; generally speaking, results are considered in percentages so if the levels are 50mL/minute, this indicates that 50% of kidney function has been lost. Loss of kidney function may be caused by several different problems or illnesses, including reduced blood flow to the kidneys, congestive heart failure, diabetes, acute or chronic kidney failure or dehydration. Decreased kidney function may be temporary or long-term; the tests may be repeated to monitor the patient’s condition.

Certain types of medication, including cisplatin and aminoglycosides, may decrease the creatinine clearance results, while diuretics can increase the measurement.

Specific Blood Tests

© Medic8® | All Rights Reserved