Method for detecting blood urea nitrogen

Claim 1

An improved method for the determination of blood urea nitrogen in blood serum or plasma, which comprises; a. providing three separate reagent reservoirs, each containing (i) an acid catalyst reagent which will promote the conversion of diacetyl monoxime to diacetyl and which will catalyze the reaction of said diacetyl with urea to form a colored complex; and each containing (ii) a frangible capsule disposed within each of said reservoirs for enclosing under hermetic conditions (iii) a color developing reagent; such color developing reagent consisting essentially of diacetyl monoxime, thiosemicarbazide and anhydrous ethylene glycol being so enclosed by said frangible capsule; b. breaking said capsule within each of said reservoirs thereby bringing said color developing reagent into admixture with said acid catalyst reagent in each of the three reservoirs; c. adding a measured proportion of blood serum or plasma to the mixture of reagents obtained in one of said reservoirs in step (b) above and a measured proportion of urea to a second of said reservoirs; d. heating the three mixtures contained by said three reservoirs after step (c) above, to a temperature of about 100° C. for a period of from about 10 to about 15 minutes; e. cooling the heated mixtures of step (d) to a temperature of from about 15° C. to about 20° C. and allowing the cooled mixtures to stand for a period of from about 3 to about 5 minutes; f. observing the degree of color developed by said color developing reagent in each of said cooled mixtures of step (e), within about 15 minutes of cooling the heated mixture; and g. comparing the degree of color developed in the three mixtures.