Diagnostic accuracy of Clauss and prothrombin time–derived fibrinogen against rotational thromboelastometry FIBTEM-A5

Background: Fibrinogen levels may fall early in major hemorrhage. The Clauss assay (Fib-C) is the laboratory gold standard, while the prothrombin time-derived assay (Fib-D) is a rapid, lower-cost alternative. Objectives: To compare Fib-C and Fib-D with viscoelastic-derived clot firmness. Methods: Data from all Queensland Health hospitals were extracted (2019-2025). Rotational Thromboelastometry FIBTEM-A5 was the reference standard. Paired Fib-C and Fib-D results with FIBTEM-A5 were analyzed. The primary outcome was correlation with FIBTEM-A5; secondary analyses assessed predictive performance for FIBTEM-A5 of ≤ 10 mm. Results: < .05). Conclusion: Fib-C aligns more closely with viscoelastic clot firmness than Fib-D. These results support Fib-C as the preferred assay and discontinuing routine Fib-D reporting in critical bleeding.