BUN Levels

Blood Urea Nitrogen (BUN) is the amount of urea nitrogen present in the blood and BUN test is a laboratory blood test performed to check its levels. The term, "urea nitrogen present in the blood", can be explained as, the amount of nitrogen present in the blood that comes from urea.

Urea is an end product formed after food metabolism and digestion. When protein is broken down into amino acids in the liver, these amino acids are catabolized into ammonia. Further, all the ammonia molecules come together to form urea. This urea is then transferred to the kidneys, through the bloodstream. The urea is then excreted from the kidney in the form of urine. Thus, blood urea nitrogen test helps in cross checking the functioning of both, kidneys and liver.

This test is also performed to find out whether the kidney disease in a patient is progressing. Sometimes, the BUN test may be performed to verify the effect of treatment provided for a particular kidney disease. This was a brief information on blood urea nitrogen definition. Now, let us know what are the normal levels of urea nitrogen in the blood, and how can abnormal BUN levels affect your health.

Normal BUN Levels

Many a time, BUN test is carried along with another blood test, named creatinine test. Creatinine is also a waste product that is excreted through the kidney and any problem in the levels of creatinine can indicate kidney problems. When both these tests are taken together, BUN and creatinine levels are measured in the form of ratio. The levels of BUN vary with age, thus, normal levels of BUN for adults is 7 to 20 mg/dL, while that for children it is, 5 to 18 mg/dL. 20:1 is considered as the normal BUN to creatinine ratio and any ratio greater or less than this normal level can indicate renal problems.

Elevated and Low BUN Levels

Low levels of BUN are usually rare and are caused due to dysfunction of the liver. Over hydration, low-protein diet and malnutrition are other major causes of decreased levels of BUN. Decreased levels is not a cause of concern, when compared to elevated levels. Increased level of BUN is also referred as azotemia and indicates improper functioning of the kidneys. When the kidneys are not working properly, they are unable to filter all the urea passed by the liver and hence, much of the urea remains in the blood.

The symptoms of elevated BUN levels include, fatigue, nausea, insomnia, dry itchy skin, etc. Given below are some of the major causes that can lead to an increase amount of BUN in the blood.

• Congestive heart failure
• Excessive protein levels in the gastrointestinal tract
• Kidney disease
• Kidney failure
• Urinary tract obstruction
• Gastrointestinal bleeding
• Dehydration
• High protein diet
• Stress or shock

Levels of BUN in Animals

BUN levels in dogs are measured to assess the kidney function and the normal levels are between 8 to 28 mg/dL. Many of the veterinarians take the help of BUN test to diagnose kidney problems in dogs. Elevated BUN is one of the major symptoms of kidney failure in cats. Thus, BUN levels in cats also play an important role and help in finding out whether the feline kidneys are working properly.

Blood Urea Nitrogen (BUN) test is a very useful blood test that can help to determine various health problems. I hope this article has helped you understand the importance of the BUN test.