"This study on automated thromboelastometry demonstrated a dose-dependent prolongation of HEPTEM CT when heparin concentration increased from 0 to 6 IU/mL. Furthermore, ROC analysis on the ability of HEPTEM CT to detect heparin concentrations of ≥ 4 IU/mL indicated possible diagnostic potential. These novel findings suggest that HEPTEM CT is a feasible ROTEM Sigma parameter for semiquantitative assessment of heparin concentrations required for safe CPB. However, this remains to be verified in future clinical studies."

"The administration of fibrinogen concentrate rapidly increased blood fibrinogen levels and significantly reduced the 3 min bleeding amount. In addition, significant improvements in extrinsic and intrinsic coagulation abilities were observed with the administration of fibrinogen concentrate."

"In pregnant patients presenting to the ED with vaginal bleeding before 20 weeks, ROTEM differences were not different in comparison to healthy pregnant patients at the same gestation stage. This suggests that ROTEM clotting profiles may not be useful in the evaluation of vaginal bleeding within this population."

"This is the first study to systematically compare multiple next generation VET and platelet aggregation systems in both healthy and septic patients under controlled PTS transport conditions. It is hypothesized that PTS-induced acceleration may alter test results. Identifying a critical threshold could ensure safe, rapid blood transport without compromising diagnostic quality, potentially reducing personnel needs and expediting therapy initiation."

Postpartum haemorrhage remains a global priority requiring rapid intervention for acute obstetric coagulopathy. This review confirms that visco-elastic haemostatic assays (VHAs) effectively reduce transfusion needs, especially when guiding fibrinogen replacement at updated thresholds (FIBTEM A5 $\le$ 8 mm). While tranexamic acid (TXA) is a mandatory therapeutic cornerstone upon diagnosis, its prophylactic use in low-risk cases lacks evidence. Ultimately, integrating VHAs into clinical practice provides a safe, data-driven approach to improving maternal outcomes.

"Similar relationships between FIBTEM and CF were observed for single and dual anti-platelet FIBTEM systems in TICH. Thresholds for fibrinogen replacement may be generalisable between single and dual anti-platelet FIBTEM systems; however, external validation is necessary."

"For the first time, we developed a comprehensive understanding of the coagulopathic profile of VM and the role of endothelial dysfunction in its pathogenesis. These findings will enable the implementation of targeted therapies based on the individual coagulation profiles."

"ROTEM sigma expedites the detection of clinically significant coagulopathy in isolated TBI. EXTEM and FIBTEM CT values are more rapidly attainable than INR and comparable in predicting head injury-related death."

In summary, this study demonstrates that TAVR patients exhibit a more prothrombotic state in the early perioperative period compared to PCI and SAVR cohorts. These findings suggest that the coagulation dynamics of TAVR are distinct, thereby challenging the current clinical practice of extrapolating antithrombotic guidelines directly from PCI data.

The dual platelet-inhibited ROTEM® Sigma FIBTEM assay shows a stronger correlation with Clauss fibrinogen but requires a lower intervention threshold. To accurately detect the critical level of 2 g/l or less in postpartum haemorrhage, the FIBTEM A5 threshold should be updated from 11 mm or less to 8 mm or less to avoid unnecessary fibrinogen replacement.

"The ROTEM delta and sigma devices had comparable performance [with ROTEM sigma]. A negative bias was observed in the FIBTEM assay with lower extrapolated clinical decision points for a delta-guided treatment algorithm for the FIBTEM and EXTEM A5."

"Both the ACT-LR and ACT+ tests of Hemochron Signature Elite device and the INTEM:HEPTEM CT ratio of ROTEM Sigma device have poor ability to detect residual heparin shortly after protamine administration."

VHA-guided MHP showed marked variation with inconsistent transfusion thresholds [ROTEM® Sigma and TEG 6 s platforms within major haemorrhage protocols]. For similar clot kinetics, dosing of blood products and haemostatic agents differed, particularly PCC. Patients with the same coagulopathy may receive different treatment across hospitals. Centralised standardisation could improve PBM consistency.

"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."

While new cartridge-based VHA devices simplify point-of-care testing, their clinical value is not yet fully established. Current research highlights a lack of interchangeability between devices and a shortage of data linking them to patient outcomes or comparing them to rapid conventional assays. Consequently, despite their technical promise, robust randomized clinical trials are still required to prove their utility in critical care settings.

"ROTEM sigma, TEG 6S, and Quantra performed similarly for exploring platelet count or residual circulating heparin. Thromboelastography 6S presented a weaker correlation with fibrinogen Clauss."

Modern cartridge-based VET - specifically the TEG 6s, HemoSonics Quantra, and ROTEM sigma - offers superior portability and ease of use compared to traditional laboratory methods. Despite limited randomized evidence for these new-generation devices, VET-guided algorithms effectively reduce blood product usage without compromising patient outcomes. Future validation of clinical cut-offs will be key to optimizing transfusion management.

ClotPro shows strong correlation with ROTEM for Maximal Clot Firmness (MCF), making these parameters clinically interchangeable in cardiac surgery. However, due to only moderate correlation and higher percentage errors in clotting times (CT) and FIB-test MCF, ClotPro requires its own specific cut-off values. While it reliably emulates ROTEM thresholds, transfusion algorithms should be adapted to the device's unique measurement profile.

"ROTEM and Sonoclot accord well on the detection of severity of coagulation dysfunction, but not on the diagnosis of the underlying cause. ROTEM correlated more closely with CCT then Sonoclot. We propose a testing strategy that could lead to a cost-effective approach to the bleeding cardiac surgery patient."

Comparison of ROTEM® Delta and ROTEM® Sigma transfusion algorithm performance in thoracic aortic surgery: a single-centre prospective observational cohort study.

"Both PCC preparations (ie, irrespective of heparin content) induced significant elevation of thrombin generation, which was not depicted by conventional coagulation tests or VHA. Our in vitro results suggest that diagnostic assays routinely used to guide PCC administration might not adequately reflect thrombin generation in bleeding patients."

"This study demonstrates the reliability of considering early ROTEM (TEM International Inc.) results and the feasibility of using PLTEM A5 to predict platelet counts and so, improve our ability to decide the need of platelet transfusion in cardiac surgery patients."

"During PPH (≥1000 mL or cases of clinical concern about bleeding), ROTEM Sigma Fibtem A5 can detect fibrinogen ≤2 g/L and guide targeted fibrinogen replacement. Laboratory results should continue to be used to guide platelet and FFP transfusion."

"These results suggest that ROTEM®-based algorithms may be transposed from one trauma centre to another independently of the setting and the ROTEM® device in use."

"The authors present the first ROTEM sigma-based algorithm for the treatment of coagulopathic bleeding. The algorithm uses parameters with optimal sensitivity and specificity for critical values of SLTs determined from a heterogenous group of donors."

The ROTEM®sigma demonstrates diagnostic accuracy comparable to the ROTEM®delta for identifying post-bypass hypofibrinogenaemia. With high specificity and low false-negative rates (2–3%), it serves as a reliable cartridge-based alternative for guiding coagulation management in cardiac surgery.

"Reference ranges for patients undergoing cardiac surgery differed from the manufacturer reference ranges. Pre-operatively, female patients exhibited a slightly more hypercoagulable ROTEM profile than males when comparing medians, though the reference ranges were similar. No differences were found across age categories. Cardiovascular-specific, but not sex- or age-specific ROTEM sigma reference ranges might be needed."

The study by Schenk et al. fails to establish valid reference ranges for the ROTEM® sigma due to a critically small sample size that lacks the statistical power required for population data. Furthermore, the lack of rigorous Bland–Altman analysis and specific ranges for sex and pregnancy means that ROTEM® delta values cannot be used interchangeably with the newer system, leaving the ROTEM® sigma reference ranges currently undefined.

Adding a FIBTEM/EXTEM clotting time ratio > 1.0 to standard ROTEM amplitude criteria significantly improves the positive predictive value and specificity for identifying hypofibrinogenaemia in cardiac surgery. This simple, cost-free adjustment helps reduce false positives and unnecessary fibrinogen administration without sacrificing sensitivity.