Cryofibrinogen involves precipitation of fibrinogen in the cold. It may be an in vitro phenomenon or it may be associated with clinical symptoms.


Clinical conditions associated with cryofibrinogen:

(1) metastatic malignant disease

(2) autoimmune disease

(3) multiple myeloma

(4) normal individuals (may show low concentrations)


Clinical findings - variable, may show:

(1) purpura or ecchymoses, especially in cold weather

(2) retinal hemorrhage or retinal vein thrombosis

(3) digital gangrene or ulceration


Laboratory findings:

(1) amorphous globules seen in the peripheral blood smear

(2) WBC count of a chilled specimen falsely elevated on an automated cytometer (due to precipitated fibrinogen being read as cells)

(3) prolonged thrombin time and decreased fibrinogen in refrigerated specimen

(4) normal thrombin time and fibrinogen in specimen kept at 37°C (collected in citrate and kept at 37°C continuously)


False positive: Specimen collected in heparin (heparin-protein cryoprecipitates may form)


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