Urea

Urea in the biochemical analysis of blood

Urea is the end product of protein and amino acid breakdown, produced in the liver and excreted by the kidneys. Its level reflects:

Kidney function (the main marker of nitrogen metabolism).
Protein balance (nutrition, tissue breakdown).
Liver function (urea synthesis).

Norm of urea in the blood

Category	Reference Values (mmol/L)
Adults	2.5–8.3
Elderly	Up to 10.0 (age-related decline in kidney function)
Children	1.4–6.4 (lower due to active growth)
Pregnant Women	Decreased by 10–20% (physiological hemodilution)

Note:

Standards may vary depending on the laboratory.
Men have slightly higher urea levels than women (due to their greater muscle mass).

Deviations from the norm

1. Increased urea (uremia, azotemia)

Reasons:

Kidney failure (acute or chronic).
Dehydration (vomiting, diarrhea, lack of drinking).
High-protein diet (meat, sports nutrition).
Massive tissue breakdown (burns, injuries, tumors).
Difficulty in the outflow of urine (stones, prostate adenoma).

Symptoms of excess:

Weakness, fatigue (intoxication with nitrogenous substances).
Nausea, vomiting (gastrointestinal irritation).
Itching of the skin(urea deposits in the skin).
The smell of urine from the mouth (uremic ‘aroma’).
Edema, decreased urine volume (in case of renal failure).

How dangerous is it?

Uremic coma with critical elevation (> 50 mmol / l).
Damage to the heart, nervous system (due to toxins).

2. Reduced urea

Reasons:

Fasting, low-protein diet (veganism, anorexia).
Severe liver diseases (cirrhosis, hepatitis – urea synthesis is impaired).
Hyperhydration (excess water in the body).
Pregnancy (physiological dilution of blood).

Symptoms of deficiency:

Weakness, loss of muscle mass (lack of protein).
Edema (with hypoproteinemia).
Jaundice, ascites (with liver failure).

How dangerous is it?

Hypoproteinemia → reduced oncotic pressure → edema.
Hepatic encephalopathy (with cirrhosis-ammonia does not turn into urea).

Additional tests

To clarify the diagnosis, prescribe:

Creatinine (a more accurate marker of renal function).
GFR (glomerular filtration rate).
Liver tests (ALT, AST, bilirubin).
Electrolytes (potassium, sodium).

What should I do if there are deviations?

If urea is elevated:

Heavy drinking (if there is no kidney failure).
Reduction of protein in the diet (on the recommendation of a nephrologist).
Treatment of the underlying disease (hemodialysis for CRF).

If urea is low:

Correction of nutrition (sufficient amount of protein).
Treatment of the liver (for cirrhosis).

Important!

Urea is a secondary marker of renal function. A more accurate indicator is creatinine and GFR.
Consultation with a doctor (nephrologist, hepatologist, therapist) is mandatory!