Urea

What is urea?

Urea is a waste product formed in your liver when protein is broken down as a natural process. It is released by the liver into your blood and carried to the kidneys. Here, the kidneys filter it out of the blood and release into the urine. This process is continuous, so there is usually a small but stable amount of urea in the blood.

Diseases or conditions that affect the kidneys or liver therefore, have the potential to affect the amount of urea present in your blood. The kidneys have great capacity for filtering our body’s waste. If one of your kidneys is fully functional, you urea levels can be completely normal if there is significant dysfunction in the other kidney.

Why analyse urea?

Urea is one of the tests measured to evaluate the health of your kidneys as part of a routine health check up. It is also measured to help diagnose kidney disease if have symptoms or are at high risk of developing kidney disease.

It is measured at regular intervals in people with known kidney disease to monitor the effectiveness of dialysis and other treatments.

High urea levels

A raised urea result may mean your kidneys are having difficulty filtering waste products out of the blood. The result will be assessed along with your other kidney blood tests creatinine and eGFR to gain a more complete picture of your kidney function.

Symptoms of kidney disease may include the following:

  • Tiredness, lack of concentration
  • Swelling around the eyes, face, wrists, abdomen, thighs, or ankles
  • High blood pressure
  • Mid-back pain, below the ribs, near where the kidneys are located
  • Problems urinating, such as a decreased volume of urine, or a change in the frequency of urination.
  • Urine that is foamy, bloody, or coffee-colored

*Urea levels can increase with the amount of protein in the diet. High-protein diets might cause abnormally high levels

Low urea levels

Low urea levels are not usually a cause for concern. The most common cause is overhydration, having too much fluid in the body. Another possible cause could potentially be malnutrition or a very low protein diet.

Rarely, urea levels can be low as a result of decreased production of urea by the liver. However, this only occurs when there is significant liver damage or disease. The urea test is not usually used to diagnose or monitor any of these conditions.


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