Assays and reference materials for current and future applications of heparins

Heparin is widely used in the prevention and treatment of thrombosis. However, this complex polysaccharide is biologically active in many systems other than coagulation, due to its structural similarity to the cell surface and matrix glycan heparan sulphate. These properties give rise to a number of potential therapeutic applications, such as those involving the anti-inflammatory activity of heparin. The anticoagulant activity of heparin is used to determine the potency of heparin preparations for use as antithrombotics. Several types of assay are used, and reference materials are available for their calibration. There is no equivalent measure of heparin's activity in other applications. For new types of heparin preparation, physicochemical methods of ensuring consistency and stability will be important, and new in vitro assays will have to be developed, all of which will require reference materials.