Precipitating Plasma

An adult female diagnosed with granulomatosis with polyangiitis was admitted for treatment with immunosuppressive medication. When a stored lithium-heparin tube was retrieved for additional testing, the plasma was found to contain a precipitate that dissolved upon heating to 37°C. Cryoprecipitate testing on fresh serum and plasma collected in prewarmed tubes with prewarmed needles was performed. Visual precipitates and immunofixation results are shown in Fig. 1. ... ... The answers are below. Cryoprecipitation in plasma, but not serum, is consistent with cryofibrinogenemia (1, 2). The heparin plasma cryoprecipitate mainly consisted of fibrinogen and fibronectin. Part of the cryofibrinogen observed in this patient was caused by a heparin-precipitable fraction as the citrate plasma cryoprecipitate was significantly smaller (3–5). Cryofibrinogenemia may be primary or secondary to autoimmunity, infection, or malignancy (1, 2). Its association with skin-lesions and systemic thrombosis is strongest when observed in citrate plasma as this distinguishes cryofibrinogenemia from heparin-induced precipitation (1–5).