Measurement of functional fibrinogen levels using the Thrombelastograph

Study ObjectiveTo validate a Thromboelastograph (Haemoscope Corporation, Niles, IL) assay for functional fibrinogen.DesignCorrelation study of the Thromboelastograph assay with two conventional fibrinogen assays by the standard Clauss method.SettingResearch laboratory of a university medical center.Participants and InterventionsBlood samples were obtained from 19 healthy volunteers.Measurement and Main ResultsThromboelastograph assays, using heparinized whole blood from 19 healthy donors, indicated that reptilase-XIIIa mixture (Activatorf)–generated clot shear elasticity in dynes per square centimeter (Gf) correlated with fibrinogen (mg/dL). Blood from four donors was used to define the contribution of hematocrit (Hct) to Gf by titration with platelet-rich plasma. The Gf versus Hct gave linear correlations (r2 = 0.746) with Gf = 1258 − 17.8 × % Hct. A commercial collection of 19 normal, 10 borderline, and one deficient for functional fibrinogen-citrated plasmas was assayed for Gf after recalcification using Activatorf. 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 ActivatorfGf with functional fibrinogen (r2 = 0.940) with Gf = −730 + 9.21 × fibrinogen (mg/dL).ConclusionThrombelastography with Activatorf may be used to determine fibrinogen levels in whole blood.