Serum urea test measures the level of urea in the blood, a waste product formed in the liver during protein metabolism. The kidneys are responsible for filtering urea from the blood and excreting it through urine. This test plays an important role in assessing kidney function. A high serum urea level may indicate that the kidneys are not functioning effectively and are unable to filter and remove waste products from the blood. In addition, urea levels can also be affected by other factors such as dehydration or a high-protein diet. Therefore, the serum urea test is a useful tool for diagnosing and monitoring the health and function of the kidneys.