The Development of a Cellulosic Material Based Method for Heparin Therapy Monitoring

Abstract

We have developed a non-clotting based heparin assay. It is established by the attachment of protamine (a heparin antidote) to a porous filter paper strip; and the subsequent migration of heparin sample through the filter paper in an ascending or descending manner. The area of paper to which heparin adsorbed will be proportional to the heparin level in the sample. This region is visualized by spraying methylene blue NNX (a dye that interacts with heparin and the interaction causes a metachromatic shift of the dye’s absorption maximum from blue to purple) solution onto the paper strip upon the exhaustion of the sample reservoir. This approach has proven to be capable of detecting and differentiating plasma heparin level within clinical range in a relatively time efficient and accurate manner.