title: Lack of effect of heparin on factor XIa.
mesh_terms: D005172:Factor XI / Q000187:drug effects*; D015945:Factor XIa; D006493:Heparin / Q000494:pharmacology*; D006801:Humans; D066298:In Vitro Techniques
chemical_list: D006493:Heparin; D005172:Factor XI; D015945:Factor XIa