Removal of heparin and protamine from plasma

Abstract

A simple chromatographic technique for rapid adsorption of heparin and protamine from plasma samples is described, allowing accurate interpretation of coagulation screening tests and specific clotting factor assays. With the use of columns of ECTEOLA-cellulose, up to 300 U. of heparin could be completely adsorbed from a 1 ml. plasma sample. When citrated nonheparinized plasma was passed over the ECTEOLA-cellulose columns, the thrombin, prothrombin, and partial thromboplastin times were unaffected. Levels of fibrinogen, prothrombin, and factors V, VII, VIII, IX, and XI average within 90 per cent of control, nonchromatographed samples. When heparinized plasma samples (0.1 and 1.0 U. per milliliter) were passed over columns, heparin was completely removed and the results of the screening tests and the specific factor assays were the same as for the chromatographed nonheparinized samples. In addition, heparinized samples with decreased factor VIII activity maintained their pretreatment factor VII activities after heparin removal. Blood samples containing heparin were obtained from two patients during open-heart surgery. Following heparin adsorption on ECTEOLA-cellulose columns, factor VIII activity levels remained above 60 per cent during cardiopulmonary by-pass. The presence of protamine sulfate in plasma samples prolonged the prothrombin and partial thromboplastin times while slightly shortening the thrombin time. The protamine effect persisted after ECTEOLA-cellulose, but could be removed by a similar column of carboxymethyl-cellulose. The latter resin had no effect on screening tests or on assays of factors VIII or IX activity. The combination of the two resins was then used to remove the separate inhibitory effects from heparinized plasma samples to which protamine had been added.