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Blood Urea Nitrogen (BUN)
Measurements of urea nitrogen are used in the diagnosis and treatment of certain renal and metabolic disorders.
Blood Urea Nitrogen (BUN) levels are a measure of kidney function and also of prerenal and postrenal conditions. Prerenal causes of elevated BUN include cardiac decompensation, water depletion or increased protein catabolism. Among the renal causes of increased levels are acute glomerulonephritis, chronic nephritis, polycystic kidney, nephrosclerosis, and tubular necrosis.
In this method, urea is hydrolyzed enzymatically by urease to yield ammonia and carbon dioxide. The ammonia and a-oxoglutarate are converted to glutamate in a reaction catalyzed by L-glutamate dehydrogenase (GLDH). Simultaneously, a molar equivalent of reduced NADH is oxidized.Two molecules of NADH are oxidized for each molecule of urea hydrolyzed. The rate of change in absorbance at 340 nm, due to the disappearance of NADH, is directly proportional to the BUN concentration in the sample.
Collect: Serum Separator Tube (SST) - 0.5 ml serum
Specimen preparation: Serum free from hemolysis is the recommended specimens. Allow blood samples to clot (15 mins). Separate the serum from the cells by centrifuging for 10 minutes. Store serum at 2-8°C until analysis.
Stability: Samples are stable up to 24-hours at room temperature (18 - 25°C), several days when refrigerated (2 - 8°C), and 2 - 3 months when frozen (<-20°C).
At Accu Reference: Refrigerated -7 days: Frozen- 1 monthNOTE: * This test is approved for all states. *
Accu Reference Medical Laboratory
|Cross Reference:||Blood Urea Nitrogen (Urea Nitrogen, Serum or Plasma), BUN (Urea Nitrogen, Serum or Plasma)|
Adults: 7 - 25 mg/dL
The assay Reportable Range is from 2.0 to 130 mg/dL. Samples exceeding the upper limit of linearity are diluted and repeated.