Blood coagulation & fibrinolysis : an international journal in haemostasis and thrombosis
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The 'derived' fibrinogen method is commonly used for the measurement of plasma fibrinogen. This method is not a direct quantitation of plasma fibrinogen, but an estimation of the fibrinogen concentration from the clotting curve of the prothrombin time on automated photo-optical coagulometers. An increasing number of laboratories are now routinely using this method to cope with increasing demands for fibrinogen testing. ⋯ The discrepancy between 'derived' and Clauss fibrinogen levels was greater in certain patient groups, e.g. patients receiving oral anticoagulants, than in normal controls. Some patients with documented hypodysfibrinogenaemia with low fibrinogen levels by Clauss assay gave normal 'derived' fibrinogen values. Although the 'derived' fibrinogen assay is rapid, economical and easily available to laboratories with suitable instruments, this study shows that it lacks standardization and is inaccurate compared with the Clauss assay.