Diseases & Conditions A - Z
powered by Talix

Urine Urea Nitrogen Test

What Is the Urine Urea Nitrogen Test?

Your body creates ammonia when it breaks down protein from foods. Ammonia contains nitrogen, which mixes with other elements in your body, including carbon, hydrogen, and oxygen to form urea. Urea is a waste product that is excreted by the kidneys when you urinate.

The urine urea nitrogen test determines how much urea is in the urine to assess the amount of protein breakdown. The test can help determine how well the kidneys are functioning, and if your intake of protein is too high or low. Additionally, it can help diagnose whether you have a problem with protein digestion or absorption from the gut.

Purpose of a Urine Urea Nitrogen Test

Your doctor will usually recommend a urea test to determine protein levels in the body. The test can determine how much protein you are eating, and if it is an adequate amount. In addition, your urea nitrogen levels may rise if you are going through heart failure or dehydration.

A common test for urea nitrogen is the blood urea nitrogen test, better known as BUN. This article refers to the urine urea nitrogen test, which is performed using a urine sample.

A urea nitrogen test can also:

  • assess how well the kidneys are functioning
  • determine if you have kidney disease
  • monitor your kidney disease
  • help diagnose a number of diseases and disorders that may affect how your kidneys function

Urine Urea Nitrogen Test Process

The urine urea nitrogen test involves analyzing urine samples that you collect during a specified 24-hour period.

It may seem awkward or uncomfortable to urinate into a cup, but no physical discomfort should occur. Follow your doctor’s orders about how to collect the sample. Generally, you will maintain normal eating and drinking habits during the collection phase.


Wash your hands carefully before and after collecting each sample. Also, make sure that you cap the containers tightly. Label and return the samples to the doctor as instructed. Samples need to be refrigerated during the 24-hour period.

On the first day of collection, you will not collect the urine first thing in the morning. Note the time, and then collect all urine for the remaining 24 hours.

Once collected, the urine is sent to the laboratory for analysis.

Understanding Your Test Results

A normal urea level in the urine is 12 to 20 grams over 24 hours.

Low levels of urea in the urine may suggest:

  • malnutrition
  • too little protein in the diet
  • kidney disease

High levels of urea in the urine may suggest:

  • too much protein in the diet
  • excessive protein breakdown in the body

Your doctor will contact you to go over your results once your urine samples have been analyzed. They may need to order more tests or physical exams before they are able to give you a diagnosis. 

Content licensed from:

Written by: Amber Erickson Gabbey
Medically reviewed on: Jan 13, 2016: Steve Kim, MD

This feature is for informational purposes only and should not be used to replace the care and information received from your health care provider. Please consult a health care professional with any health concerns you may have.
Symptom Search
Enter your symptoms in our Symptom Checker to find out possible causes of your symptoms. Go.
Drug Interaction Checker
Enter any list of prescription drugs and see how they interact with each other and with other substances. Go.
Pill Identifier
Enter its color and shape information, and this tool helps you identify it. Go.
Drugs A-Z
Find information on drug interactions, side effects, and more. Go.