Analysis of protein C and protein S in disease states.

Protein C and protein S are two vitamin K dependent plasma proteins which function in concert to serve as a natural anticoagulant. Deficiencies of both proteins are associated with thrombotic disease. Assay procedures employing monoclonal antibodies are discussed and compared to previous assay procedures. The assays are effective in patients undergoing heparin or oral anticoagulant therapy and are not influenced by inhibitory factors generated during intravascular coagulation. These assays should aid in our understanding of the role of protein C and protein S in thrombotic disease.