Analyses on Heat-coagulated Blood and Serum. I. the Determination of Uric Acid.

A method for the quantitative separation of serum urate from the proteins present, that does not employ chemical precipitation, is presented. The separation is accomplished by heat coagulation of serum and the subsequent aqueous extraction of the purine from the intact coagulum. Serum is placed at the bottom of a container of sufficient size to permit the formation of a thin layer and then coagulated in a boiling-water bath. The resultant coagulum is firm, adherent to the container, and not easily disrupted. Water is then added to cover the coagulum and the urate extracted. The urate present in the extract is determined using a phosphotungstate reduction method.