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 (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 x % 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 Activatorf Gf with functional fibrinogen (r2 = 0.940) with Gf = -730 + 9.21 x fibrinogen (mg/dL).

Conclusion: Thrombelastography with Activatorf may be used to determine fibrinogen levels in whole blood.