LabCorp Test

Urea Nitrogen Urine Test, 24-Hour

Quick Overview

Renal function test; coarse nitrogen-wasting test on patients on hyperalimentation; indicate nitrogen balance in hyperalimentation; rule out tap of urinary bladder in amniocentesis, paracentesis.

Test #003541


Availability: In stock

Also Known As BUN, Nitrogen Balance Study, Urine Urea, Urine Urea Nitrogen
Preparation Urinate at 8am and discard the specimen. Then collect all urine in 24-hour period, ending with final collection at 8am the next morning. Refrigerate the collected urine between all voidings or keep it in a cool place. Screw the lid on securely. Transport the specimen promptly to the laboratory. Container must be labeled with full name, date and time collection started, and date and time collection finished.
Test Results 1-2 days. May take longer based on weather, holiday or lab delays.

Used in the diagnosis of certain renal and metabolic diseases.

The determination of urea is the most widely used test for the evaluation of kidney function. The test is frequently used in conjunction with the determination of creatinine for the differential diagnosis of prerenal hyperuremia (cardiac decompensation, water depletion, increased protein catabolism), renal hyperuremia (glomerulonephritis, chronic nephritis, polycistic kidney, nephrosclerosis, tubular necrosis) and postrenal hyperuremia (obstructions of the urinary tract).Urea is the final degradation product of protein and amino acid metabolism. In protein catabolism the proteins are broken down into 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.

About 80% of urinary nitrogen is in the form of urea which is the major end product of protein metabolism. Urea excreted in the urine is the primary method of nitrogen elimination; therefore, this test provides an approximate evaluation of nitrogen balance. Conditions associated with increased urine urea nitrogen are hyperthyroidism, high protein diets and post-operative states. Decreased levels are associated with convalescence, liver disease, toxemia and advanced renal disease.

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