A rapid method for the determination of urea in blood and urine.

PURPOSE of this report is to present a rapid method for the determination of urea in blood and urine based upon the urea-pdimethylaminobenzaldehyde reaction. Ehrlich, Rhode, Brocher, Weltmann and Barrenscheen, and Werner (1-5) reported on numerous substances that form red, orange, violet, and yellow interaction complexes with p-dhnethylaminobenzaldehyde. Activated carbon has the specific property of adsorbing strongly aromatic substances (6). By treating the blood and urine with activated carbon, these interfering substances are removed. Thus, when deproteinized and carbon-treated ifitrates of blood and urine are reacted with our modified Ehrlich reagent, an immediate, clear, stable yellow complex is formed. These same filtrates incubated with urease and then reacted with p-dimethylaminobenzaldehyde did not form colored complexes. The method described here is based upon the above-mentioned principles.