What Is The Relation Between High BUN And Kidney Function

We often chronic kidney disease (CKD) patients say they have high blood urea nitrogen(BUN). It seems that BUN is related with kidney function. Is this true? What is the relation between BUN and kidney function?

First, we should know how is BUN used?

The blood urea nitrogen or BUN test is mainly used, along with the creatinine test to evaluate kidney function in a range of circumstances, to diagnose kidney disease, and to monitor people with acute or chronic kidney dysfunction or kidney failure. Besides, it also may be used to evaluate a person’s general health status.

Second, when is it ordered?

BUN is often ordered along with creatinine test when kidney problems are suspected. Signs or complications of kidney dysfunction may include:

A decrease of urine output

Swelling or puffiness, particularly around the eyes or in the face, hands, ankles, and feet

Foamy, bloody or coffee-colored urine

Fatigue, poor concentration, poor appetite or sleeping difficulties

Back pain or abdominal pain

High blood pressure

What does increased BUN test mean?

Increased BUN levels indicated impaired kidney function. This may be caused by acute or chronic kidney disease, damage, or kidney failure. Also a condition that leads to decreased blood flow to the kidneys, such as congestive heart failure, shock, severe burns, obstruction of urine flow or dehydration can be a cause of high BUN.

Why does high BUN level occur with CKD?

Blood Urea Nitrogen is another measure of wastes (urea) in the blood. Urea is produced from the breakdown of protein already in the body and protein in your diet. Normally, BUN can be disposed out by the kidneys. Once kidneys are damaged, its filtering function will be affected, a high BUN usually means that kidney function is less than normal.

A BUN test is a measure of kidney function, but other factors may also affect BUN level, such as bleeding in the intestines, congestive heart failure, and certain medications. Furthermore, though BUN has something with kidney function, it can not be the only measure to evaluate kidney function. Measures of kidney function include serum creatinine, creatinine clearance, glomerular filtration rate, urine albumin and microalbuminuria.