Elevated BUN

BUN stands for Blood Urea Nitrogen and BUN test is a laboratory blood test performed to measure the amount of urea nitrogen present in the blood. Or, in other words, this test measures the amount of nitrogen in the blood that comes from urea. Urea is basically a waste product formed in our body during protein metabolism. It is produced in our liver, filtered in the kidneys and is then flushed out of the body through urine. The BUN test is performed to check whether the kidneys are functioning properly or not. When the physician suspects kidney failure or kidney disease, he asks for a BUN test for evaluation of the kidney function. If the patient is already suffering from a kidney problem, this test may help in analyzing the results of the treatment provided by the physician.

If the BUN levels are not normal then it indicates that the body's flushing system is not working properly. Elevated BUN levels is a sign of kidney dysfunction, while low BUN levels can indicate liver problems. Sometimes the BUN test is also done along with a blood creatinine test. Creatinine is also a waste product that is filtered by kidneys. So high levels of creatinine can indicate kidney damage. Both these tests can be used together to find out the BUN to creatinine ratio. The physician may also ask to perform a BUN test to diagnose other health ailments like urinary tract obstruction, congestive heart failure, liver disease, etc. Now let us take a look at the causes of elevated BUN levels.

Causes of High BUN Levels

BUN levels change with age and they are very low in babies and can be higher in case of adults more than 60 years of age. Men usually have higher BUN levels as compared to women. The normal range of the BUN level is 7 to 20mg/dL and any reading above or below these values can indicate high or low BUN levels, respectively. Elevated BUN level is also referred as azotemia. One of the major causes of elevated BUN and high creatinine levels, is improper kidney function. Healthy kidneys can filter all the urea passed to them through the bloodstream from the liver, while damaged kidneys are unable to clear this urea from the bloodstream. Other than kidney problems, dehydration is another cause. To confirm whether dehydration is the cause of elevated BUN level, the BUN to creatinine ratio test is taken. This is because when the BUN level is high due to dehydration, creatinine levels are normal. Thus, when BUN to creatinine ratio is high, dehydration can be a possible cause of elevated BUN level.

On the other hand elevated BUN creatinine levels, can indicate that kidneys are not functioning properly. Diabetes or hypertension can be the causes of elevated levels of BUN and creatinine. Even some medications like antibiotics, anti-inflammatory medication and gout medication affects the BUN level. High protein diet and heart failure are some other causes of elevate BUN levels. Given below is a list that will summarize the major causes.

• 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

Though urea is not too toxic in nature, but high levels of urea in the blood can show certain symptoms. Dry-itchy skin, insomnia, nausea, fatigue, etc. are some of the common symptoms.

Not just in humans, but elevated BUN in dogs can also be an indication of kidney dysfunction. Healthy pets usually display low or normal levels of BUN, but sometimes pets with kidney problems show a drastic elevation in their BUN levels. Veterinarians usually carry the BUN test for dogs with kidney problems, to test whether the treatment provided is effective or not.

Test results which show elevated BUN levels can indicate serious problems in kidney functioning. So, if you are suffering from any of the problems that can lead to an elevated BUN level, get a BUN test done and confirm whether your BUN levels are normal or not.