New enzymatic method for determining D-arabinitol in serum

A new reagent has been developed to determine D-arabinitol. This utilizes D-arabinitol 2-oxidoreductase derived from Bacillus sp. with high stability, and water-soluble tetrazolium salt, that can detect NADH with high sensitivity. Since this enzyme does not react to D-mannitol, elimination of D-mannitol is unnecessary. Thus, this is a much simpler process than currently available with commercial kits use D-arabinitol 4-oxidoreductase. The within-run and between-run precisions (CV) were 2.4-6.9% and 3.1-8.7%, respectively, whilst the correlation (r) between the results obtained with our proposed method (y) and those obtained with the commercial "Arabinitec-auto" kit (x) was 0.964 (y = 1.02x + 0.933 mumol/l; n = 69). However, some samples deviated remarkably from correlation in both methods. Our analyzing accuracy is satisfactory in clinical application, as it does not miss positive sample over cut-off value. We are refining this method by investigating why some specimens are apart from correlation significantly.