Abstract Number: PB0660
Meeting: ISTH 2020 Congress
Background: Available fibrinogen assays have some limitations. The Clauss fibrinogen assay is influenced by fibrin(ogen) degradation products (FDPs). Immunological assays with monoclonal antibodies are also affected by degraded forms of fibrin(ogen) and cannot differentiate between fibrinogen and fibrin and between intact and fragmented molecules. On this knowledge, we have developed a novel chromogenic method of measuring plasma fibrinogen levels without interference by FDPs, not dependent on a clotting reaction or antibodies, and adaptable to all chromogenic or fluorogenic microplate readers. The test principle is based on a competition between fibrinogen and a synthetic peptide substrate for cleavage by the snake venom derived thrombin-like enzyme batroxobin.
Aims: To compare the new chromogenic fibrinogen assay with the Clauss fibrinogen assay in citrated plasma from healthy individuals.
Methods: Citrated plasmas from healthy donors (n=15) were tested by Clauss fibrinogen assay performed on BCS XP using Multifibren U reagent and by our new chromogenic fibrinogen assay performed on a microplate reader, using Ci-Trol 1 plasma (specification: 2.4 – 3.0 g/L) as calibrator. Samples were diluted to cover wider fibrinogen concentration range. FDPs of known concentrations were spiked into the enzyme kinetic reaction to determine interfering effects of FDPs.
Results: Fibrinogen levels of healthy patients closely match when the two assay methods are compared (Clauss assay mean = 2.6±0.3 g/L; chromogenic assay mean = 2.9±0.2 g/L) and a comparison plot was constructed with R2=0.92. While observable interference in fibrin clotting was detected, FDPs at 57 µg/mL did not affect the novel chromogenic assay.
Conclusions: Fibrinogen levels measured in healthy plasma by the novel chromogenic fibrinogen assay and the Clauss assay were similar. However, on the contrary of the clot-based method, the novel chromogenic method was not interfered by FDPs. Our new fibrinogen assay allows the fast detection of intact (non-proteolysed) fibrinogen.
To cite this abstract in AMA style:Pun S, Nienhold N, Ritschl A, Janssen M, Casini A. A Novel Quantitative Chromogenic Fibrinogen Assay Adaptable to Centralized Laboratory Analyzers [abstract]. Res Pract Thromb Haemost. 2020; 4 (Suppl 1). https://abstracts.isth.org/abstract/a-novel-quantitative-chromogenic-fibrinogen-assay-adaptable-to-centralized-laboratory-analyzers/. Accessed November 26, 2020.
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