A blood urea test measures the level of urea in the blood. Urea is a waste product that is produced when protein is broken down in the body. The test is used to evaluate kidney function and to help diagnose and monitor kidney disease.

There is no specific preparation required for a blood urea test, but it is generally recommended to fast (not eat or drink anything) for at least 8 hours before the test.

The test is performed by taking a small sample of blood from a vein in the arm. The blood sample is then sent to a laboratory for analysis.

The test is commonly prescribed for people who have symptoms of kidney dysfunction, such as fatigue, swelling in the legs, and a decrease in urine output. It is also used to monitor people who have a known kidney disorder or who are at risk of developing one.

The reference range for blood urea varies but is generally considered to be between 7 and 20 mg/dL. However, normal values can vary depending on factors such as the person’s age, sex, and overall health.

It’s important to note that this test is not a definitive diagnosis and it is recommended to consult with a doctor and get a proper diagnosis with clinical examination and other tests. Also, Other factors such as diet, medications and other medical conditions can affect the results of this test. Therefore, a single test result should not be used to diagnose or exclude kidney disease.