Measurement of functional fibrinogen levels using the Thrombelastograph

Abstract Study Objective To validate a Thromboelastograph (Haemoscope Corporation, Niles, IL) assay for functional fibrinogen. Design Correlation study of the Thromboelastograph assay with two conventional fibrinogen assays by the standard Clauss method. Setting Research laboratory of a university medical center. Participants and Interventions Blood samples were obtained from 19 healthy volunteers. Measurement and Main Results Thromboelastograph assays, using heparinized whole blood from 19 healthy donors, indicated that reptilase-XIIIa mixture (Activator f )–generated clot shear elasticity in dynes per square centimeter ( G f ) correlated with fibrinogen (mg/dL). Blood from four donors was used to define the contribution of hematocrit (Hct) to G f by titration with platelet-rich plasma. The G f versus Hct gave linear correlations ( r 2 = 0.746) with G f = 1258 − 17.8 × % Hct. A commercial collection of 19 normal, 10 borderline, and one deficient for functional fibrinogen-citrated plasmas was assayed for G f after recalcification using Activator f . Of the 30 plasma samples, four were from factor X– or factor VII–deficient donors and one was from a coumadin-treated donor. There was a linear correlation of Activator f G f with functional fibrinogen ( r 2 = 0.940) with G f = −730 + 9.21 × fibrinogen (mg/dL). Conclusion Thrombelastography with Activator f may be used to determine fibrinogen levels in whole blood.