Kidney Function Tests Health Article

Definition

Kidney function tests is a collective term for a variety of individual tests and procedures that can be done to evaluate how well the kidneys are functioning. A doctor who orders kidney function tests and uses the results to assess the functioning of the kidneys is called a nephrologist.

Purpose

The kidneys, the body's natural filtration system, perform many vital functions, including removing metabolic waste products from the bloodstream, regulating the body's water balance, and maintaining the pH (acidity/alkalinity) of the body's fluids. Approximately one and a half quarts of blood per minute are circulated through the kidneys, where waste chemicals are filtered out and eliminated from the body (along with excess water) in the form of urine. Kidney function tests help to determine if the kidneys are performing their tasks adequately.

Precautions

The doctor should take a complete history prior to conducting kidney function tests to evaluate the patient's food and drug intake. A wide variety of prescription and over-the-counter medications can affect blood and urine kidney function test results, as can some food and beverages.

Description

Many conditions can affect the ability of the kidneys to carry out their vital functions. Some conditions can lead to a rapid (acute) decline in kidney function; others lead to a gradual (chronic) decline in function. Both can result in a build-up of toxic waste substances in the blood. A number of clinical laboratory tests that measure the levels of substances normally regulated by the kidneys can help to determine the cause and extent of kidney dysfunction. Urine and blood samples are used for these tests.

The nephrologist uses these results in a number of ways. Once a diagnosis is made that kidney disease is present and what kind of kidney disease is causing the problem, the nephrologist may recommend a specific treatment. Although there is no specific drug therapy that will prevent the progression of kidney disease, the doctor will make recommendations for treatment to slow the disease as much as possible. For instance, the doctor might prescribe blood pressure medications, or treatments for patients with diabetes. If kidney disease is getting worse, the nephrologist may discuss hemodialysis (blood cleansing by removal of excess fluid, minerals, and wastes) or kidney transplantation (surgical procedure to implant a healthy kidney into a patient with kidney disease or kidney failure) with the patient.