Urea
At a Glance
Why Get Tested?
To evaluate kidney function and monitor the effectiveness of dialysis
When to Get Tested?
If you have non-specific symptoms that may indicate a kidney problem
Sample Required?
A blood sample drawn from a vein in the arm
The Test Sample
What is being tested?
Urea is produced when protein is broken down by the body. Healthy kidneys eliminate more than 90% of the urea the body produces, so blood levels indicate how well your kidneys are working.
How is the sample collected for testing?
A blood sample is drawn from a vein in the arm.
Is any test preparation needed to ensure the quality of the sample?
No test preparation is needed.
The Test
How is it used?
Urea and creatinine levels are used to evaluate kidney function and to monitor patients with kidney failure or those receiving dialysis.
When is it requested?
Urea may be used in a panel of tests:
- when someone has non-specific illness,
- as part of a routine testing panel, or
- to check how the kidneys are functioning before starting to take certain drugs.
Urea is often ordered with creatinine:
- if kidney problems are suspected,
- to monitor treatment of kidney disease, or
- to monitor kidney function while someone is on certain drugs.
What does the test result mean?
High urea levels suggest impaired kidney function. This may be due to acute or chronic kidney disease. However, there are many things besides kidney disease that can affect urea levels such as decreased blood flow to the kidneys as in congestive heart failure, shock, stress, recent heart attack or severe burns; bleeding from the gastrointestinal tract; conditions that cause obstruction of urine flow; or dehydration.
Low urea levels are not common and are not usually a cause for concern. They can be seen in severe liver disease or malnutrition but are not used to diagnose or monitor these conditions. Low urea is also seen in normal pregnancy.
Is there anything else I should know?
Urea levels increase with age and also with the amount of protein in your diet. High-protein diets may cause abnormally high urea levels. Very low-protein diets can cause abnormally low urea. Lower urea levels are also seen in infants and small children.
Drugs that impair kidney function may increase urea levels. Your urea and creatinine may be monitored if you are on certain drugs.
Common Questions
Ask a Laboratory Scientist
Article Sources
NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.
