Cryoglobulins and Cryofibrinogenemia

Cryoglobulins are immunoglobulins that precipitate from serum at temperatures less than core body temperature and resolubilize when rewarmed to 37°C. Cryoglobulinemia encompasses a set of clinical disorders and laboratory findings; it is a subset of a larger group of syndromes characterized by the induction of clinical and/or laboratory abnormalities. Cryofibrinogenemia is a misnomer and actually describes cold-precipitable complexes of fibrin and fibrinogen which also contain fibronectin. This chapter presents two case examples of pathologic fibrinemia. Cryofibrinogenemia may result from elevated levels of fibrin-fibrinogen complexes in plasma, be a manifestation of dysfibrinogenemia, be secondary to cold insolubility of fibronectin, or rarely, result from complexing with monoclonal antifibrinogen antibodies. Cryofibrinogenemia can be identified by cryoprecipitation or freeze-thawing of plasma collected in citrate that contains an inhibitor of thrombin generation.