An improved reagent system for the measurement of serum uric acid.

The reagent is modified as follows: Serum chromogens are destroyed by trisodium phosphate. The use of phosphotungstic acid eliminates the tungstate and sulfate anions, a frequent cause of turbidity. Triethanolamine, added to the carbonate-urea mixture, provides unusual stability of the color through its buffering action. Only 0.2 ml of serum is required. The method is highly reproducible and accurate; analytical results agree closely with those obtained by the uricase or cyanide-urea method.