Urea in the urine

Urea is the final product of protein breakdown in the body. When excreted through the kidneys, the residues of "unnecessary" nitrogen are removed. It is formed in the liver.

It is excreted together with urine and partially with sweat (which gives sweat a specific smell). Urea helps the body retain water and some trace elements. This is done by reabsorption by the kidneys into the bloodstream. Every time the absorption process takes place, urea "pulls" water and mineral molecules back into the bloodstream.

However, its excessive content harms organs and tissues. Monitoring the urea content in urine is necessary to control protein metabolism (nitrogen balance). Normally, when consuming 100 g of protein, 500 mmol of urea is excreted per day in the urine.

Knowledge of the nitrogen balance of severe patients provides information to intensive care physicians about the specifics of intravenous nutrition. If increased protein breakdown prevails in the body - it is necessary to increase the amount of protein in intravenous solutions; with reduced - vice versa.

The level of urea depends on the balance of its formation and removal from the body. A decrease in concentration is possible with a low-protein diet or starvation, liver disease, poisoning with chemicals (arsenic, phosphorus-containing compounds), during pregnancy, after hemodialysis.

Reduction of urea in urine is observed in: liver and kidney disease, starvation, during convalescence, pregnancy, that is, with a positive nitrogen balance - less is excreted than incoming. A positive nitrogen balance (excretion exceeds the intake of protein into the body) occurs in cases of: increased thyroid gland function, diabetes, fever, after extensive surgery.