Urea Assay Kit

Summary & Explanation

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, polycystic 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 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. In 1914 Marshall introduced an assay based on the enzyme urease for determining urea in blood. The ammonia released from urea by urease was measured titrimetrically. Numerous other techniques have since been employed to measure the ammonia produced. These include Bertholot’s indophenol assay and the reaction of ammonia with Nessler’s reagent. Subsequent modifications have been published by Fawcett and Scott and by Chaney and Marbach. In 1995, Talke and Schubert published a totally enzymatic procedure for the determination of urea using the coupled urease/glutamate dehydrogenase (GLDH) enzyme system. The Analyticon UREA/BUN assay is based on the completely enzymatic method. It has been optimized for automatic analyzers that permit kinetic measurements.