Introduction: Congenital fibrinogen disorders (CFDs) are classified as afibrinogenemia or hypofibrinogenemia (Hypo), dysfibrinogenemia (Dys), or hypodysfibrinogenemia (Hypodys), according to functional and antigenic fibrinogen concentrations. However, in routine laboratory tests, plasma fibrinogen levels are mostly measured using the functional Clauss method and not as an antigenic level. Therefore, it is difficult to discriminate CFD from acquired hypofibrinogenemia (aHypo). To establish a screening method for CFD, we investigated the parameters of clot waveform analysis (CWA) from the Clauss method.
Methods: We compared fibrinogen concentrations determined using Clauss and prothrombin time (PT)-derived methods for 67 aHypo and CFD cases (19 Dys, 4 Hypodys, and 1 Hypo determined using antigen levels and DNA sequence analysis) with a CS-2400 instrument, and the CWA parameters, dH and Min1, were analyzed automatically with an on-board algorithm. dH and Min1 are the maximum change in transmittance at the end of coagulation and the maximum velocity of transmittance change during coagulation, respectively.
Results: Clauss/PT-derived ratios detected 18 cases of Dys and Hypodys but no Hypo cases, whereas Clauss/dH plus Clauss/Min1 ratios were calculated from fibrinogen concentration using the Clauss method and CWA parameters detected 21 cases of Dys and Hypodys and one Hypo case. Moreover, the Clauss/PT-derived ratio and Clauss/dH plus Clauss/Min1 ratio detected 22 cases of Dys and Hypodys cases and one Hypo case.
Conclusion: This report demonstrates that CWA parameters of the Clauss method, Clauss/dH plus Clauss/Min1 ratio, screened Dys patients with a higher rate, whereas Clauss/PT-derived ratios did not.
Keywords: Clauss method; clot waveform analysis; congenital fibrinogen disorders; fibrinogen.
© 2020 John Wiley & Sons Ltd.