Evaluation of the fibrinogen antigenic turbidimetric assay as a screening method for measurement of fibrinogen concentration in dogs

Abstract

A novel method for the rapid detection of fibrinogen concentration in human plasma, the fibrinogen antigenic turbidimetric assay (FIATA), is based on the precipitation of fibrinogen by vancomycin and a resultant change in optical density. The objectives of this study were to evaluate the FIATA method for: (1) measuring fibrinogen concentration in canine plasma using specimens collected in citrate, EDTA, and heparin, (2) species-specific calibration requirements, and (3) applicability for automation. Standard curves were generated with both human and canine fibrinogen standards in the FIATA, and a reference interval for fibrinogen concentration was established using citrated plasma from healthy dogs (n = 127). Using specimens collected from this population, results using the FIATA were compared with a modified thermoprecipitation method, and 24 of the FIATA samples were used for comparison with a particle-enhanced turbidometric fibrinogen assay. The FIATA was also applied to an automated chemistry analyzer using citrated plasma. Fibrinogen concentration was measured in EDTA and heparinized plasma in the manual FIATA. Standards, methods, and anticoagulants were compared, and correlation among these variables was evaluated. Significant differences between FIATA results using human and canine standards and the manual and automated methods were not found. For EDTA plasma, fibrinogen concentrations were not identical, but were similar, to those for citrated plasma; heparinized plasma was not suitable for measurement. Correlation between the thermoprecipitation method and FIATA was weak. The reference interval for fibrinogen as measured by the FIATA using citrated plasma was 103-456 mg/dL. The FIATA can be used as a screening method to measure fibrinogen concentration in citrated or EDTA plasma from dogs.