Fibrinogen levels in severe trauma: A preliminary comparison of Clauss Fibrinogen, ROTEM Sigma, ROTEM Delta and TEG 6s assays from the FEISTY pilot randomised clinical trial.

OBJECTIVE: To describe the relationships between different methods of measuring functional fibrinogen levels in severely injured, bleeding trauma patients across multiple timepoints during hospitalisation.

METHODS: In 100 adult trauma patients enrolled in the FEISTY pilot randomised clinical trial at four tertiary trauma centres in Australia, blood samples were collected prospectively. Consistency of agreement was calculated, comparing functional fibrinogen levels measured by four methods - ROTEM® Delta and Sigma FIBTEM A5, TEG® 6s CFF MA, and gold-standard Clauss Fibrinogen.

RESULTS: Comparing the ROTEM® Delta and new-generation ROTEM® Sigma machine, consistency of agreement for FIBTEM A5, measured by calculating intraclass correlation coefficients (ICCs), was ≥0.73 across all analysed timepoints, with mean differences (Sigma minus Delta) of 0.10-3.57 mm. Corresponding values comparing the ROTEM® Sigma FIBTEM A5 and TEG® 6s CFF MA were ICC = 0.55-0.82 and ICC = 4.69-7.97 (CFF MA minus A5). Comparing ROTEM® Sigma FIBTEM A5 and Clauss Fibrinogen Analysis (CFA), among statistically significant simple linear regression models, R2 was 0.25-0.67, and comparing TEG® 6s CFF MA and CFA (CFA) 0.65-0.82, although not all differences were significant with the latter comparison. Relationships across all timepoints combined were Clauss Fibrinogen (CF) (g/L) = 0.21𝑥 + 0.004 (where 𝑥 = ROTEM® Sigma FIBTEM A5 in mm) and (g/L) = 0.16𝑥 - 0.06 (where 𝑥 = TEG® 6s CFF MA in mm).

CONCLUSIONS: The present study revealed acceptable agreement between four different assays measuring functional fibrinogen, with current- and previous-generation ROTEM® machines (Sigma, Delta) performing similarly measuring functional fibrinogen via FIBTEM assay. This suggests that haemostatic resuscitation algorithms designed for the ROTEM® Delta can be applied to the ROTEM® Sigma to guide fibrinogen replacement.