Urea is a breakdown product of the amino acids that make up proteins. In the liver, proteins are converted into ammonia, carbon dioxide and water (especially when energy is needed). Ammonia is toxic and must therefore be excreted. This process starts in liver by converting ammonia into non-toxic urea. This compound is taken up by the kidneys and excreted in the urine. After excretion, it is converted back to ammonia by bacteria, giving urine its characteristic odour. Any condition that prevents the renal excretion of urea causes an increase in urea and nitrogen wastes in the blood (uraemia). This can lead to serious life-threatening problems. High osmolality (pressure) in cerebrospinal fluid. Eye fluid to leaks into the intercellular fluid and plasma, resulting in fluid imbalance in the eye. When urea is high, dialysis may be needed to remove urea from the blood. Blood Urea Nitrogen (BUN) is the expression of urea as Nitrogen. In some cases, this test is not informative since it does not express the exact urea molecule but includes other sources of nitrogen in the blood. However, it can give information about liver damage, urinary tract obstruction, congestive heart failure, gastrointestinal bleeding, but high BUN also gives information about dehydration and impaired kidney function.
Interpretation:The BUN test is particularly important in diabetic patients and in patients with high blood pressure to recognise any kidney function disorder. It is also a liver damage, urinary tract obstruction, congestive heart failure and gastrointestinal bleeding indicator. If there is a kidney problem, the BUN measurement should be investigated with a creatinine test. High BUN levels are called uraemia. Uraemia results in fluid imbalance, electrolyte, hormonal imbalances, and metabolic problems due to impaired renal function. Uremia symptoms are characterised by nausea, vomiting, fatigue, anorexia, weight loss, muscle cramps, mental changes, itching, visual disturbances and thirst. Serious consequences include seizures, coma, cardiac arrest, gastrointestinal bleeding, osteoporosis due to renal failure and hyperglycaemia. Low BUN may indicate malnutrition due to very low protein diet or severe liver damage. Urea can be converted to BUN by dividing by a factor of 0.357. The BUN/creatinine ratio is 1:10. Some clinicians use this ratio to describe dehydration leading to increased uraemia.
Sample: Arm venous blood. Fasting is necessary.
Working day: Everyday
Result Time: Same day, 2 hours
