To evaluate kidney function and monitor the effectiveness of dialysis
Urea Test
If you have non-specific symptoms that may suggest a kidney problem or if you are suddenly ill or have a long term illness that may cause or be made worse by kidney disease
A blood sample taken from a vein in the arm
None
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How is it used?
Urea and creatinine levels are used to evaluate how well the kidney is working and to monitor patients with kidneys that are diseased or those receiving kidney dialysis.
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When is it requested?
Urea may be used in a panel of tests:
- when someone has non-specific illness,
- as part of a routine group of tests, or
- to check how the kidneys are functioning before starting to take certain drugs.
Urea is often requested with creatinine:
- if kidney problems are suspected,
- to monitor treatment of kidney disease, or
- to monitor kidney function while someone is on certain drugs
Some symptoms and signs of kidney dysfunction include:
- Tiredness, lack of concentration, poor appetite, poor sleep
- Swelling or puffiness (oedema) around the eyes, wrists, ankles or tummy
- Urine that is foamy, blood strained or coffee-coloured
- A decrease in the amount of urine
- Problems urinating such as a burning sensation, abnormal discharge during urination or a change in the frequency of urination especially at night
- Mid-back pain below the ribs where the kidneys are located
- High blood pressure
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What does the test result mean?
High urea levels suggest poor 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 levels are also seen in normal pregnancy.
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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 levels. Lower urea levels are also seen in infants and small children.
Drugs that damage kidney function may increase urea levels. Your urea and creatinine may be monitored if you are on certain drugs.
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What other tests are used with urea to check how my kidneys are functioning?
Urea and creatinine are often the first tests that are used to check how well the kidneys are able to filter waste products from your blood. Your doctor may also request electrolyte tests such as sodium and potassium, or calcium to help understand how your kidneys are functioning.
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How does urea change with age?
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What happens to urea in pregnancy?