Measurement of Fibrinogen Concentration in the Plasma of Dogs: A Comparison Between Heat Precipitation and Modified Thrombin Clotting Time Method

Fibrinogen is a glycoprotein that plays a key role in blood clotting and is also a non-specific indicator of inflammation. The most widely used techniques for measuring plasma fibrinogen concentration include heat precipitation (Millar’s technique) and modified thrombin clotting time (Clauss method). Both techniques have been automated in a haematology analyzer (QBC-Vet Autoreader®, IDEXX; Millar’s technique) and in a newly developed semi-automatic mechanical and optical detection coagulometer (MC1 Plus®, DIASys Greiner GmbH; Clauss method). The purpose of this study was to compare the results of the above mentioned techniques for the measurement of fibrinogen concentration in the plasma of dogs. Fibrinogen concentrations were measured with both techniques in the plasma of 85 clinically normal dogs and of 43 dogs with diseases that have been previously associated with dysfibrinogenemia. Passing-Bablock’s regression and Bland Altman difference plots were used for the comparison of the results of the two techniques. No correlation was found between the results of the two techniques; thus the two techniques cannot be used interchangeably. Measurement of fibrinogen concentration with the heat precipitation method is more applicable for single sample analysis, while the modified thrombin clotting time method is more practical for analyzing stored frozen samples and thus for research purposes.