What Does Kidney Function Test Mean?
A kidney function test may be any one of several tests designed to assess how well the body's kidneys are working. Both urine and blood tests are used to assess kidney function. Testing may involve providing a single urine or blood sample or the collection of a urine sample over a 24-hour period.
WorkplaceTesting Explains Kidney Function Test
There are several different types of kidney function tests. One common test is urinalysis, which is used to detect abnormal levels of protein in the urine. An additional test is called the glomerular filtration rate (GFR). This test measure the rate at which blood passes through the glomeruli, the part of the kidneys that filter the blood, using a calculation based on the creatinine levels present in a blood sample. A creatinine clearance test also measures creatinine levels, but does so by assessing a 24-hour urine collection sample.
Other kidney function tests include a measure of blood urea nitrogen (BUN) and dissolved salts such as sodium, potassium, chloride, and bicarbonate.
When functioning properly, the kidneys serve as filters, removing impurities from the blood. A physician will order one or more kidney function tests if he or she suspects that a patient's kidneys are not properly filtering waste and contaminants from the person's blood stream. These tests measure the concentration of various substances in the blood or urine. An elevated concentration of one or more of the measured substances may indicate that it is not being properly removed by the kidneys.