Development and Clinical Evaluation of Two Chromogenic Substrate Methods for Monitoring Fondaparinux Sodium

Abstract

This study was designed to develop methods for monitoring of the selective factor Xa inhibitor fondaparinux sodium (ARIXTRA®) based on standard laboratory methods for the chromogenic determination of the anti-factor Xa activity of low molecular weight heparin. To examine the biologic activity of fondaparinux in comparison to its plasma concentration, 2 methods were investigated: 1 working with the addition of antithrombin (AT), the other without exogenous AT. Both methods showed a linear relationship of fondaparinux concentration and OD/min on a log-lin scale in the range from 0.1 to 2 μg/mL. Inter- and intra-assay variability was