Synonyms

   Blood Urea Nitrogen (BUN)

Clinical Significance

   It is useful for screening test for evaluation of kidney function

Specimen

   Serum

Stability

   Refrigerated (preferred) : 7 days

   Frozen : 365 days

Reference Range

   2.7 – 8 mmol/L

Interpretation

   Increased blood urea nitrogen (BUN) may be due to prerenal causes (cardiac decompensation, water depletion due to decreased intake and excessive loss, increased protein catabolism, and high protein diet), renal causes (acute glomerulonephritis, chronic nephritis, polycystic kidney disease, nephrosclerosis, and tubular necrosis), and postrenal causes (eg, all types of obstruction of the urinary tract, such as stones, enlarged prostate gland, tumors).