Urea is a product formed in the liver during the breakdown of proteins.
Proteins are part of our daily diet. They are broken down in the liver into building blocks (amino acids), which in turn are used to produce other proteins needed by the body. During the breakdown urea is also released which is not reused. It is filtered from the blood in the kidneys and removed through the urine.
Because we eat protein every day and also break it down, there is always a small amount of urea present in the blood. If the kidneys are not functioning properly, urea is not excreted and the amount in the blood will increase.
The kidneys are very important for human health because they remove breakdown products and harmful substances from the blood. When the kidneys are not working properly due to disease, these substances accumulate in the body.
Kidney problems occur in various diseases. Therefore, urea (along with creatinine) is often part of a general blood test.
Some drugs are removed from the body by the kidneys. To make sure that not too much medicine remains in the blood, the doctor sometimes requests a urea test to examine the function of the kidneys before prescribing the medicine.
A slightly elevated blood urea level may indicate a kidney problem because the kidneys are not filtering blood properly. It may also be that the blood flow through the kidneys is not good. This occurs, for example, with dehydration, heart problems, stress, severe burns, blockages in the urinary tract and after a heart attack. Urea levels can also be slightly elevated when there is increased protein breakdown or after a high-protein meal. This is different in every patient and will need to be assessed by the physician. In addition, a slightly elevated urea value often occurs in pregnancy. This is not a problem.
If the urea level in the blood is very high, the kidneys are not working properly.
Often a lowered urea value does not mean anything, but it may also be that the liver is not working properly and the breakdown of proteins is disturbed. In that case, specific tests are needed to examine liver function (such as ALAT, ASAT, alkaline phosphatase). Urea is not used for testing liver function. A lowered urea value can also indicate malnutrition which means the body is not getting enough protein.
This involves a urea blood test from serum