What is a 24-hour Urinary Urea Test?
Urea is a waste product of protein metabolism in the liver. It is excreted through urine by filtration of the kidneys. The liver breaks down the protein from food and sends it to the kidneys to be filtered from the blood and excreted through urine. The amount of urea excreted in urine is vital in the evaluation of kidney function.
24-hour urinary urea test measures the excreted urea in urine within 24 hours. This test helps in the assessment of the body’s hydration status, dietary protein intake, and the metabolism and functioning of the kidneys.
How is the Test Performed?
The 24-hour urinary urea test is a straightforward test that requires the collection of urine for 24 hours.
Preparation
- You should avoid food that may alter the urine color.
- Keep yourself hydrated a day before the test as well as during the test
- Certain medications and dietary supplements would be instructed to avoid by the healthcare provider. Always discuss any medication you are taking with your healthcare provider.
Collection Process
- In the morning discard the first urine of the day of the test and note that time.
- Collect all following urine in the container treated with special preservatives that are provided by the laboratory for 24 hours including the urine of the next morning.
- Collect every drop of urine for true results.
- Keep the container in a cool place like a refrigerator or on ice to prevent sample degradation and contamination.
Submission
Label and seal the container properly and return it to the laboratory.
Analysis
Total urea excreted in 24 hours is measured in the laboratory based on the concentration and volume of the urea excreted.
In addition to a urinary urea test a blood test might also be suggested to measure serum urea or blood urea nitrogen (BUN) levels.
What are the symptoms that prompt this test?
A 24-hour urinary urea test is usually recommended for individuals showing signs and symptoms of kidney dysfunction, protein metabolism, dehydration, or other related conditions;
General Symptoms
- Tiredness
- Lack of concentration
- Joint or bone pain
- Muscle cramps
- Dry mouth
- Swelling in hands, feet, or face (edema)
- Frequent urination
- Blood in urine
- Decreased urine output
- Unexplained weight loss
- High levels of nitrogen
What are Normal Ranges for This Test?
The normal value for a 24-hour urinary urea test is based on age, diet, and kidney function. The generally accepted value of urinary urea is
Normal Range – 12 to 20 grams/day
**The above-mentioned value is a general guideline and varies according to the method used and individual factors like dietary protein intake, hydration levels, and physical activity. Results should always be interpreted by healthcare providers according to the medical condition..**
What Happens if Test Results Show Abnormal Levels?
Abnormal urea levels indicate the presence of underlying disorders and various health conditions including kidney dysfunction, poor protein metabolism, and dehydration. Below are some conditions caused due to abnormal urea levels.
High urea levels (uremia): Elevated levels of urea suggest that kidneys are doing excessive filtration which could be caused due to;
- Kidney impairment
- High protein intake
- dehydration
Low urea levels;
- Kidney failure or renal disorders; when the kidneys are unable to filter urea from the blood it causes low levels of urea in urine
- Liver disease; As the protein metabolism occurs in the liver, it suggests that the liver is not producing enough urea thus the low levels of urea in urine.
Protein malabsorption; A low protein diet leads to lower urea production.
