The diagnosis of kidney disease, whether it is acute or chronic, is usually made from the results of several tests. Since symptoms usually appear later in kidney disease, routine lab test results may be the first indicator that kidney disease is present.

The most common tests used for the diagnosis of kidney disease include blood tests, urine tests, kidney ultrasound, and other imaging tests.

Blood and urine samples can both be used to test levels of kidney function. The kidney filtration rate can be estimated by measuring the amount of creatinine (produced by the breakdown of muscle) in the blood. The level of blood urea nitrogen (BUN) can also be tested to indicate how well the kidneys are functioning, although there are many factors that can affect the outcome of this particular test.

Perhaps the most effective way to test kidney function is to measure the kidney filtration rate (glomerular filtration rate). There are various techniques that can be used to do this. The most accurate method is to measure creatinine. The measurement of the creatinine content of a blood sample and a timed (e.g., 24-hour) urine collection allows for the accurate determination of the glomerular filtration rate. The glomerular filtration rate can also be estimated using a calculation that uses creatinine levels. Creatinine levels are a sensitive indicator of kidney function.

In addition to the use of creatinine, there are nuclear medicine scanning techniques that can give an approximate assessment of glomerular filtration in each kidney. These techniques include X-ray, intravenous urography, computed tomography (CT) scan, and magnetic resonance imaging (MRI).

A kidney ultrasound will also be used in the diagnosis of kidney disease. The ultrasound will detect abnormalities in the kidneys such as structural problems or the presence of cysts or tumors.

Written and reviewed by the MediResource Clinical Team