What is Urea?
Urea is a metabolic by-product of the process of conversion of protein into amino acids. Urea is formed in the liver and is transported by the blood to the kidneys. The kidneys then excrete the urea with urine. The Urea Test or Blood Urea Nitrogen (BUN) Test measures the levels of urea present in the blood.
Why is Urea done?
The BUN Test is performed:
· As a part of Metabolic Panel Tests for regular health checkups
· To estimate the health of the kidneys
· To diagnose kidney diseases
· To monitor the efficacy of treatments being used for kidney diseases like dialysis
What does Urea Measure?
Urea is a byproduct of protein metabolism. Proteins consumed in the diet are digested and converted into amino acids, which are utilized by the body. This metabolic process creates toxic byproduct ammonia. This byproduct is rapidly converted by the liver to form urea, which is less toxic and is transported relatively safely in blood. Following this, urea is transported by the blood to the kidneys. The kidneys then filter it out of the blood and excrete it out of the body in a solution called urine. This process continues and the body keeps producing and excreting urea, hence maintaining a low and steady level of urea in the blood.
The BUN test measures the amount of urea present in the urea. The levels of BUN test in the blood are affected due to impairment of kidney function, or due to large scale liver conditions. Primarily, BUN Test results are used to evaluate kidney functioning. Results are often interpreted together with results of Creatinine Tests that measure the levels of another metabolic waste (creatinine), which is also excreted in the urine.
Interpreting Urea results
Normal range (Approx.):
REFERENCE RANGE (mg/dL)
1 week to 1 year
Reference range may vary from lab to lab*
Higher than normal BUN levels indicate impaired kidney function which means the kidneys are unable to effectively filter waste products out of the blood.
Lower than normal BUN levels are usually clinically insignificant. However, lower levels may be associated with large scale liver conditions in some cases.