Practical issues on the laboratory monitoring of low molecular weight heparins and related polysaccharides

Today, we are limited by measurements of plasma factors that do not always relate to the overall pharmacodynamic response of a drug. Once the mechanism of action of the new glycosaminoglycans becomes better defined, the laboratory will be better equipped to target that biologic entity that is most appropriate for clinical measurement of effect. In the past, the PT and APTT have been the mainstay in the laboratory assessment of coagulation and monitoring heparin and warfarin. The development of new antithrombotic agents has shown us the limited sensitivity of these assays and the fact that they do not provide complete information of coagulation mechanisms. This brief article has addressed several of the key issues related to laboratory testing of glycosaminoglycans. Many questions remain; however, a practical approach incorporating these ideas in future developmental work should help in proper assay design.