Blood urea nitrogen (BUN) or serum urea nitrogen is the end product of the hepatic detoxification of ammonia. It is this parameter that is sometimes also used to assess liver function. Urea nitrogen concentration in blood may decrease with impaired conversion of ammonia to urea by the liver. Low serum urea concentrations are, however, not
Clinical Information. Urea is the final degradation product of protein and amino acid metabolism. In protein catabolism, the proteins are broken down to amino acids and deaminated. The ammonia formed in this process is synthesized to urea in the liver. This is the most important catabolic pathway for eliminating excess nitrogen in the human body.
Conventional urea/creatinine ratio (mg/dL)/ (mg/dL): N.b. Consider prerenal causes of kidney injury when BUN/Cr >20. SI urea/creatinine ratio (mmol/L)/ (umol/L): More notes: Low BUN/Creat ratio can be caused by: inadequate protein intake. reduced urea synthesis as in advanced liver disease. increased creatinine production as in rhabdomyolysis.Blood Urea Nitrogen (BUN) Urea nitrogen is the nitrogen portion of urea, a substance formed in the liver through an enzymatic protein breakdown process. Urea is normally freely filtered through the renal glomeruli, with a small amount reabsorbed in the tubules and the remainder excreted in the urine.
Milk urea nitrogen is the fraction of milk protein that is derived from blood urea nitrogen (BUN). In Holstein’s, MUN normally represents about 0.19 percentage points of the normal 3.2% total milk protein. Casein and/or whey proteins that contribute amino acids for human use or cheese production are not included in MUN values.