print #5319: Urea Nitrogen (BUN) 5/24/2013 Components   Name Method Reference Range Units Urea Nitrogen (BUN) S  Male < 30 days: 4 - 12 Female < 30 days: 3 - 17 Male < 12 months: 2 - 13 Female < 12 months: 4 - 14 Male < 4 years: 3 - 12 Female < 4 years: 3 - 14 Both < 20 years: 7 - 20 Both >= 20 years: 7 - 25   mg/dL   Specimen Requirements   Type Volume Temperature Instructions PRIMARY 1 Serum 1 (0.5) mL1 (0.5) mL   Ambient - 7 Day(s)/Refrigerated - 5 Day(s)/Frozen - 28 Day(s)   ALTERNATE   Plasma Heparinized 1 (0.5) mL   Ambient - 7 Day(s)/Refrigerated - 5 Day(s)/Frozen - 28 Day(s)   Clinical Utilities Urea is the principle waste product of protein catabolism. It is synthesized in the liver from ammonia which is produced as a result of the deamination of amino acids and is excreted by the kidneys. BUN is most commonly measured in the diagnosis and treatment of certain renal and metabolic diseases. Increased BUN concentration may result from increased production of urea due to (1) diet or excessive destruction of cellular proteins as occurs in massive infection and fevers, (2) reduced renal perfusion resulting from dehydration or heart failure, (3) nearly all types of kidney disease, and (4) mechanical obstruction to urine excretion such as caused by stones, tumors, infection, or stricture. Decreased urea levels are less frequent and occur primarily in advanced liver disease and in over hydration. Collection Instructions Transport room temperature. Setup Schedule Monday-Saturday Reported (Analytical Time) Same day CPT Code 84520 The CPT codes provided are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payer being billed.