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What Does High BUN Mean

2013-10-04 17:17| Font Size A A A

Blood Urea Nitrogen (BUN) is an indication of renal health. Normal ranges 3.2-7.1 mmol/L. If Glomerular Filtration Rate (GFR) and blood volume decrease (hypovolemia) then BUN will increase. Other factors responsible for its increment are fever, increased catabolism, high protein diet and gastrointestinal bleeding. However, what does high BUN mean? (Have a question? Get an answer from free online service now!)

1. Prerenal ARI


It means increased generation. The high degree is related to the original kidney function. If the kidney function were normal, BUN would increase when the digestive tract hemorrhage reach to 800 ml. If the kidney is damaged, a low hemorrhage, such as the 200 ml, can lead to high BUN.

Hypoperfusion Azotemia

It means the decreasing of renal perfusion. Due to the increasing of reabsorption, the fglomerular filtrations reduct. There are two kinds of Hypoperfusion azotemia. The first one is reduction of absolute blood volume (dehydration, blood loss, adrenocortical function reduction). The other one is reduction of effective blood volume (severe heart failure, acute myocardial infarction, cardiac tamponade, liver cirrhosis, and nephrotic syndrome).

2. Intrarenal ARI

Parenchyma azotemia refers to various solid lesions such as glomerulonephritis, interstitial nephritis, acute or chronic renal failure, renal space-occupying and destructive lesions, etc.

3. Postrenal ARI

Urinary tract obstruction lead to filtration reduction and reabsorption increases.

If urea nitrogen is high in the renal function examination, do not ignore it and do not too nervous. Although the blood urea nitrogen can be used as an index of glomerular function, but it is not as accurate as serum creatinine clinically. If your BUN is high, you are suggested to receive a comprehensive examination. You can email to for the specific inspection projects.

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