Serum urea

Urea (urea, ure) is the end product of mammalian protein catabolism. It is synthesized in the liver through the ornithine cycle and is mainly excreted by the kidneys. Because the molecular weight of urea is small and easy to dissolve, and its diffusivity is great, the urea concentration in cerebrospinal fluid, serous fluid, saliva, and sweat is basically the same. Blood urea concentration is mainly affected by renal function and protein intake and catabolism. At present, the most commonly used methods for the determination of urea in clinical laboratories are the diacetyl-oxime method and the enzyme coupling rate method.