Fructosamine Test-Plus, a modified fructosamine assay evaluated.

We have evaluated Fructosamine Test-Plus, a commercial fructosamine assay based on the reduction of nitro-blue tetrazolium dye in alkaline buffer (Clin Chem 1985;31:1550-4), modified by including a detergent and uricase in the reagent, by changing the concentrations of buffer and dye, and by changing the approach to primary calibration. Specimens were from 2321 participants in a health screening survey in a local workforce. Compared with the original fructosamine method, the Fructosamine Test-Plus method was less affected by protein concentration in the sample and less subject to interference from hyperlipidemia. The changes have also extended the linearity of the assay in the pathological range. However, as a screening method for diabetes mellitus in a population with a disease prevalence of 2.28%, the performance of Fructosamine Test-Plus was similar to the original assay.