This test is mainly used to determine a person's protein balance and the quantity of food protein required by persons with serious illnesses. It also estimates how much protein an individual consumes and how much the kidneys can eliminate urea. The examination determines how much urea the kidneys excrete.

Assessing how well your kidneys are functioning is also helpful. Urea levels in the urine will be lower than usual, and blood levels will be higher if renal function is compromised.

Symptoms may not appear immediately when the body's urea nitrogen levels vary. Multiple symptoms may be indicated by higher-than-usual variations in the urine's average urea nitrogen level. The following signs may necessitate a 24-hour urine urea nitrogen test:

• Abnormality of taste
• Insufficient urine production
• Itching
• Muscle cramps
• Mental confusion
• Severe unintentional weight loss
• Sleepiness
• Swelling
• Fatigue
• High blood pressure
• Loss of appetite
• Nausea or vomiting
• Malnutrition

Over 24 hours, the average urea level in urine is 12 to 20 grams. Individual labs may have somewhat different reference ranges depending on gender or age.

Low urea levels in the urine may indicate:

• Malnutrition
• Renal illness caused by a lack of protein in the diet

High urea levels in the urine may indicate:

• The diet contains a significant amount of protein.
• A high rate of protein degradation in the body.

Once your urine samples have been examined, your doctor will contact you to review the results. They may need to order additional tests or physical exams before diagnosing.

Diagnostic centres offer a home sample collection facility for a 24-hour urine urea nitrogen test. You must collect all your urine over 24 hours. This is referred to as a 24-hour urine sample test. You will be given a unique urine collection container and instructions on collecting and keeping your samples. Your service provider will advise you when to begin, and will after 24 hours, your sample will be sent to the laboratory for testing.