KIDNEY FUNCTION TESTS: Blood Urea Nitrogen (BUN) and Creatinine

 

What Do the Kidneys Actually Do?

Your kidneys play a very important role in your life. They filter waste materials from your blood

and get rid of unwanted chemicals in your urine. Their function is critical to your good health.

 

How Do I Know if My Kidneys are Working Right?

Most doctors will order a couple of different blood tests to make sure your kidneys are working well. These are called a blood urea nitrogen (BUN) and a creatinine test and will usually be part of your annual check-up, especially if you've had swelling (edema) of your ankles or if you've had urinary problems.

 

The BUN will measure the amount of nitrogen you have in your blood. Nitrogen is a part of each

cell in your body. As cells die, the body can recycle and use some of the nitrogen. What the

body can't recycle, it must eliminate through the kidneys. In someone suffering from kidney

disease, the nitrogen accumulates in the body and the BUN level rises.

 

Creatinine is another body chemical that helps the kidneys get rid of nitrogen. It is a natural

breakdown product of muscle tissue. High creatinine levels will alert your doctor to poor kidney

function. Some drugs can also increase your body's creatinine levels. Just to make sure your

kidneys are doing their job, your doctor may want to order a creatinine level, especially if you're

taking certain prescription drugs.

 

What Will Cause High Levels of BUN/creatinine?

- Kidney Disease

- Body's Response to Certain Prescription Drugs

- Severe, Prolonged Exertion

 

What Will Cause Low Levels of BUN/Creatinine?

- Deteriorated Nutritional Status -- Especially in Older Adults