Urea

Urea is the chief end product of protein metabolism. it is formed in the liver from ammonia and excreted by the kidneys. Urea accounts for 50% of serum non-protein nitrogen

Causes of Increased serum urea

1. Reduced Renal excretion
   • Pre-renal failure
     • Renal hypoperfusion (Shock, dehydration)
     • Volume contraction
     • Decreased effective circulating volume
   • Renal failure
     • Acute and chronic intrinsic renal disease
     • Nephrotoxic drugs
   • Post renal obstruction
2. Increased protein turnover
   • Increased catabolism (burns, sepsis)
   • Increased protein intake

Causes of Decreased serum urea

1. Reduced protein intake
   • High CHO. Low protein diets
   • Malabsorption states
   • Alcoholism
   • Malnutrition
2. Reduced protein catabolism
   • Severe hepatic damage
3. Increased anabolic state
   • Late pregnancy
   • Infancy & childhood
   • Acromegaly
4. Drugs
   • Chloramphenicol
5. Other
   • Over-hydration