Abstract
Summary
1. The platelet concentration influences the sensitivity of bloods and plasmas to the effect of added heparin. The anticoagulant potency of heparin is also enhanced by prothrombin deficiency. The potentiated effect of heparin in thrombocytopenic bloods may be due to reduced thromboplastin (cephalin) activity.
2. The protamine titration may be increased when the platelet count is normal and it may be normal in the presence of thrombocytopenia. It is influenced by heparin, heparinoid substances, prothrombin deficiency, hemophilia, and possibly other factors.
3. Increased protamine titrations may occur in bleeding patients who have no other apparent clotting defects, including the whole blood clotting time. Many of these patients cease bleeding when given intravenous toluidine blue. The protamine titration under these conditions can be returned to or toward normal regardless of the platelet level.
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