Thromboelastography and thrombin generation assay in inherited afibrinogenemia.

Fibrinogen is a glycoprotein with a crucial role in blood coagulation. Upon enzymatic cleavage by thrombin, fibrinogen is converted from its soluble form to insoluble fibrin which is key structural protein of a clot. It also participates in platelet aggregation by binding to GPIIb/IIIa. Genetic alterations can lead to either complete or partial, quantitative or qualitative defects of fibrinogen. Inherited afibrinogenemia is a rare bleeding disorder with autosomal recessive inheritance due to a complete absence of fibrinogen. The primary aim of this study was to determine whether 70 mg/kg of human fibrinogen concentrate (HFC) is an adequate dose in subjects with inherited afibrinogenemia to reach normal levels of plasmatic fibrinogen (1.5-2 g/L). Secondary aims included assessing changes in thromboelastography (TEG) and thrombin generation assay (TGA) before and after a dose of HFC. Four patients were included, and each underwent pre-and post (one time-point) HFC dose laboratory testing. Two patients needed dose adjustments to reach a normal post-dose fibrinogen level. In addition, we noted that the TEG parameter maximum amplitude (MA) improved in accordance with correction of the fibrinogen levels. TGA results were normal in all subjects. Our results suggest that individualized dosing based on fibrinogen levels may be necessary.