Comparison of a Colorimetric (automated) with an Enzymatic (manual) Uric Acid Procedure.

‘J’HE MOST COMMONLY USED METHODS for the estimation of uric acid are those colorimetric procedures utilizing the reduction of phosphotungstic acid (1-7). Since these procedures are not specific for uric acid, an enzymatic procedure utilizing uricase, which oxidizes uric acid to allantoin, has been employed by a number of investigators (8-12). The enzymatic method, dependent upon the absorption of light at 292 mp. by the uric acid molecule, is more time consuming timan the colorimetric and requires the use of a UV spectrophotometer. These limitations make it desirable to have available, particularly for large numbers of determinations, a method that is rapid, reliable, and accurate. The AutoAnalyzer,* au automated system for chemical analysis, has also been adapted for uric acid assays. The purpose of this paper is to compare, with regard to precision, similarity, and accuracy of results, a large series of uric acid determinations performed by both a colorimetric automated procedure and an enzymatic manual method.