Application of the urine protein assay to serum total protein measurement with the pyrogallol red molybdate method

Abstract

The Biuret method is the mainstay of serum total protein assay, with a prevalence of almost 100%. Therefore, it is difficult to verify abnormal data due to pitfalls such as lipoprotein-X or amino acid infusions by other methods. On the other hand, the pyrogallol red (PR) method, which is used for the urinary protein assay, has less nonspecific reactions to non-protein components such as amino acids and carbohydrates, but is not used for the serum total protein assay because of its high sensitivity. We investigated whether the JEOL JCA-BM6070, which has a sample pre-dilution function, can be used to confirm the serum protein assay obtained by the biuret method by setting appropriate parameters and adapting it to the PR method, which has fewer nonspecific reactions than the biuret method. The correlation between the PR-BM method (y) and the Biuret method (x) in 163 patient sera samples was r = 0.977, y = 1.00x + 0.07, and the measured values of both methods generally agreed. From these results, we conclude that the PR-BM method can be used as a confirmatory method for serum total protein measurement.