How To Conduct a Blood Urea Nitrogen (BUN) Test?

Submitted on March 27, 2012

What is a Blood Urea Nitrogen (BUN) Test?

The Blood Urea Nitrogen test or simply the BUN test is usually used with the creatinine test. Together, these two tests are helpful in order to evaluate the kidney problems and diseases. If a person is suffering from either chronic or acute dysfunction of the kidneys, this test is asked for on a regular basis to evaluate the damage sustained by the kidneys and to see the progress made by the treatment given.

This test may also be ordered to evaluate the general health of a person. These tests can be ordered to evaluate non specific complaints made by sick patients or a part of their routine testing. During a hospital stay, these tests are definitely performed before a person is deemed fit enough to be discharged.

High BUN levels almost always indicate a dysfunction of the kidneys. Some of the major symptoms of BUN are lack of ability to concentrate, troubled sleeping or complete sleeplessness, fatigue, puffiness in the eyes, face and wrist, change in the color of urine, abnormal discharges in the urine and high blood pressure.

Reasons Why It is Conducted

The BUN to creatinine ratio often used by comparing the ratio of the serum laboratory values of the BUN and the creatinine. This ratio is obtained to ascertain the health of the kidneys. If the BUN levels are high and the BUN to creatinine ratio is about 20:1, the renal damage has not yet begun. If the ratio is somewhere from 10:1 to 20:1, it shows the post renal disease stage. If the ratio is less than 10:1, the intrarenal disease stage is reached.

Apart from determining this ratio, blood urea nitrogen serum is often tested for the patients who are suffering from chronic conditions like diabetes, heart attacks or a congestive heart failure. The kidney functions may be checked from time to time to check for improvements in those suffering from chronic kidney diseases.

Though blood urea nitrogen elevation levels suggest a problem in the kidney function, the exact values of the levels may give a more comprehensive idea of the extent of damage due to disease. A corrective course is charted based on these values. Other conditions like severe burns or dehydration may also be a cause of these elevated levels.

Low blood urea nitrogen levels, though not always a cause for concern may be observed in people who suffer from severe liver diseases and malnutrition. If a person has been consuming too much liquid or is over-hydrated, the BUN levels may run low. However, it is rare to see low BUN levels in people.