The effect of plasmapheresis on the serum activity level of dalteparin: a case report

The effect of plasmapheresis on the anticoagulant properties of the low molecular weight heparins has never been studied. We had the opportunity to study this effect in a woman who was receiving dalteparin for the treatment of a pulmonary embolus and required plasmapheresis. Over the course of 8 days, five courses of plasmapheresis were performed. Anti-Xa activity was measured pre- and post-dalteparin administration both during and between the first three courses of plasmapheresis. Comparing the rate of change between pairs of anti-Xa activity, the absorption rate was found to have decreased by over 50%. The decay rate, as compared with a historical control, was found to have increased by over 480%. These results suggest that the level of anticoagulation of dalteparin, as monitored through an anti-Xa assay, is reduced by plasmapheresis.