Table 2.

Clinical evaluation of TEG and ROTEM functional fibrinogen tests for diagnosis of coagulopathy (hypofibrinogenemia), prediction of transfusion requirements and mortality.

Clinical settings	Study design and patients	Blood collection and analysis	Findings	Ref.
FF TEG
Trauma	Randomized controlled trial of trauma patients at risk of significant hemorrhage (n=45, ISS=18-29) receiving either 6 g fibrinogen concentrate (RiaSTAP™) or placebo (normal saline)	Citrated whole blood was collected from the randomized trauma patients at admission, 1-, 3-, 11-, 23- and 47-h post-infusion time. Standard FF TEG was performed on a computerized TEG Hemostasis System 5000 (Haemonetics Corporation, Haemoscope Division, Niles, IL, USA) according to the manufacturer's protocol.	FF TEG MA predicted hypofibrinogenemia (fibrinogen concentration < 1 g/L) and 24-h plasma transfusion with high accuracies (AUC=0.95, p=0.002 and AUC=0.70, p=0.042).	[30, 31]
	A prospective study of 182 adult trauma patients with a median ISS of 17 (9-26)	Blood was sampled immediately upon arrival to trauma centre and evaluated in tissue factor-activated and platelet inhibited TEG (i.e. FF TEG) precisely 1 h after sampling by a hemostasis analyzer system (TEG 5000, Haemonetics Corp., Braintree, MA) according to the manufacturer's recommendations. All analyses were conducted at 37°C.	Sensitivity, specificity and AUC of FF TEG MA for detection of fibrinogen < 1.5 g/L were 77%, 81% and 0.869, respectively. FF TEG MA was also a univariate predictors of massive transfusion (>10 units of RBCs) at 6 and 24 h with odd ratios of 0.79, 0.82 and mortality at 28 days with a hazard ratio of 0.84.	[35, 63]
Cardiac surgery	A prospective observational study of 105 children less than 5 years of age undergoing congenital heart surgery with CPB	Whole blood samples were collected via indwelling arterial catheters before and after CPB. FF TEG and kaolin heparinase TEG were performed on the TEG 5000 with company's reagents by a single technician, within 20 min of collection of the samples. Plasma fibrinogen levels were determined by the Clauss method using the commercial reagents and instrument (STA Fibrinogen, Diagnostica Stago).	FF TEG MA predicted hypofibrinogenemia (fibrinogen concentration < 2 g/L) with AUC of 0.71 (95% CI 0.59-0.83)	[40]
ROTEM FIBTEM
Trauma	Randomized controlled trial of trauma patients at risk of significant hemorrhage (n=45, ISS=18-29) receiving either 6 g fibrinogen concentrate (RiaSTAP™) or placebo (normal saline)	Citrated whole blood was collected from the trauma patients at admission, 1-, 3-, 11-, 23- and 47-h post-infusion time. Standard ROTEM FIBTEM was performed on a ROTEM delta system (Tem Innovations GmbH, Munich, Germany; succeeded by Instrumentation Laboratory, Bedford, MA, USA) according to the manufacturer's protocol.	ROTEM FIBTEM MCF predicted hypofibrinogenemia (fibrinogen concentration < 1 g/L) and 24-h plasma transfusion with high accuracies (AUC=0.96, p<0.001) and AUC=0.72, p=0.023).	[30, 31]
	A prospective observational study of 88 trauma patients an median ISS score of 22 (12-34)	Blood samples were collected immediately after the patient's arrival to the trauma room (H0) and at 6 h (H6), 12 h (H12) and 24 h (H24) after admission, representing a total of 270 samples. The ROTEM measurements and standard coagulation tests were performed within 2 h of collection of blood samples.	Sensitivity, specificity and AUC of FIBTEM A10 for detection of fibrinogen < 1 g/L were 91%, 85% and 0.96, respectively.	[45]
	A retrospective analysis of data from 323 patients with an injury severity score (ISS) ≥16 (20-50)	Blood samples were taken immediately upon admission to ER. ROTEM analyses (EXTEM, INTEM, FIBTEM) were typically performed at the bedside within minutes of sample collection. Fibrinogen concentration was measured by the Clauss method (STA-Fib® assay (Roche Diagnostics GmbH); optical read-out), using a STA-Compact® machine (Roche Diagnostics GmbH, Vienna, Austria).	Sensitivity, specificity and AUC of FIBTEM A10/MCF for prediction of massive transfusion (≥10 units RBC transfused in 24 h) 63.3/77.5%, 83.2/74.9%, 0.83/0.84 (95% CI 0.78-0.87/0.79-0.88), similar to fibrinogen concentration	[64]
	A prospective cohort study of 517 trauma patients with a median ISS of 14 (8-27)	Blood was drawn from either the femoral vein or antecubital fossa into a 2.7-mL citrated vacutainer within 20 min of arrival in the emergency department (ED). ROTEM tests were performed within 2 h of blood draw with a ROTEM delta instrument, at 37°C.	Sensitivity, specificity and AUC of FIBTEM A5 for detection of fibrinogen <1.5 g/L 87%, 70% and 0.8 (95% CI 0.7-0.9)	[3]
	A prospective, single-center, non-interventional, non-controlled, open clinical study of 50 trauma patients with a median ISS of 13 (4-66)	Blood was collected at hospital admission, 3- and 24-h after admission and analyzed by ROTEM assays (EXTEM and FIBTEM). EXTEM was considered positive if one of the four principle parameters (CT, CFT, MCF, and Maximum Lysis) greater than 20% of the expected highest or lowest normal value of the manufacturer normal value ranges (CT ≥ 94, CFT ≥ 190, MCF ≤ 40, ML ≤ 12). FIBTEM was considered positive if MCF was at least 20% smaller than the expected mean normal value (MCF ≤ 7).	Sensitivity, specificity and AUC of FIBTEM MCF < 7 mm within normal EXTEM patients are 100%, 90.2%, 0.951 and 0%, 87.5%, 0.563 for predictions of coagulopathy (INR≥1.3) and mortality at 30 days	[65]
	A prospective study of 182 adult trauma patients with a median ISS of 17 (9-26)	Blood was sampled immediately on hospital arrival. FIBTEM assays were performed with citrated blood precisely 1 h after sampling according to the manufacturer's recommendations. Fibrinogen level was determined by Clauss method.	Sensitivity, specificity and AUC of FIBTEM MCF < 10 mm were 80%, 89% and 0.889 for detection of fibrinogen <1.5 g/L.	[35]
	A prospective cohort study of 334 blunt trauma patients (ISS≥15 or Glasgow Coma Score ≤14).	Citrated blood was collected at hospital admission. ROTEM tests were performed according to the manufacturer's instructions, using equipment and test reagents provided by Tem International GmbH. Logistic regression models were used to evaluate ROTEM tests for prediction of 24-h death and 6-h transfusions.	FIBTEM MCF with a cut-off of 7 mm predicted the need for RBC transfusion with an odd ratio of 0.92 (95% CI 0.87–0.98)	[46]
Cardiac surgery	A prospective, observational pilot study of 35 patients undergoing elective cardiac surgery on cardiopulmonary bypass (CPB) for cyanotic congenital heart disease	Citrated blood was collected after induction of anesthesia and analyzed by ROTEM. No details were provided. Fibrinogen concentration assay was not provided.	ROTEM FIBTEM MCF is highly predictive of hypofibrinogenemia (fibrinogen <1.5 g/L) (AUC=0.99).	[47]
	A randomized, placebo-controlled trail of 116 high-risk patients undergoing cardiac surgery with CPB	ROTEM FIBTEM was performed 20 min before removal of the aortic cross-clamp, after fibrinogen supplementation. Fibrinogen concentrations were measured upon arrival in ICU according to a photo-optical Clauss method.	FIBTEM MCF with the best cut-off value of 14 mm yielded a good discriminative power for severe bleeding with an AUC of 0.721, sensitivity of 80%, specificity of 72%	[52]
	A retrospective observational study of 1077 patients undergoing cardiac surgery with CPB.	Citrated blood was collected during the rewarming phase (≥36°C). EXTEM and FIBTEM were conducted at 37°C as per manufacturer's reagents and procedures. Fibrinogen concentration was measured by the Clauss method using STAR Evolution (Stago, Paris, France).	The optimal FIBTEM A10 cut-off for diagnosis of a fibrinogen concentration <1.5 g/L was ≤8 mm with an AUC of 0.95.	[51]
	A prospective observational study of 110 patients undergoing cardiac surgery with CPB.	Citrated whole blood was sampled from a central venous line or from the extracorporeal circuit at pre-CPB, on-CPB, post-CPB. ROTEM assays of INTEM, EXTEM, FIBTEM and HEPTEM were performed at 37°C by certified bioanalytical technicians. Plasma levels of fibrinogen were measured using the Clauss technique on a coagulation analyzer (BCS, Dade Behring Inc., Germany) using the Multifibren U-Reagent according to manufacturer's specifications.	An on-CPB FIBTEM A10 ≤ 10 mm identified patients with a post-CPB Clauss fibrinogen of ≤1.5 g/L with a sensitivity of 0.99 and a positive predictive value of 0.60.	[53]
	A retrospective and observational study of 119 children <10 years old undergoing congenital cardiac surgery with CPB.	Blood was collected twice during surgery, after anesthesia induction and CPB. ROTEM EXTEM and FIBTEM were performed with citrated blood according to the manufacturer's recommendations. Intraoperative excessive blood loss was defined as estimated blood loss ≥50% of estimated blood volume. Logistic regression models were used to identify predictors for excessive blood loss.	Post-CPB FIBTEM CA10<5 mm predicted massive blood loss with an odd ratio of 11.1 (95% CI 2.6-47.3, p=0.001) and AUC of 0.83.	[41]
Liver transplantation (LT)	A retrospective observational study of 295 patients (254 living donors and 41 LT patients).	Citrated blood was collected from 1 h after induction of general anesthesia, 1 h after surgical incision, 30 min after hepatectomy, 30 min after graft reperfusion, and after hepatic artery anastomosis. ROTEM® tests (EXTEM, INTEM and FIBTEM) were routinely performed according to the manufacturer's instructions. Fibrinogen concentration was measured using the Dade thrombin reagent (Siemens Healthcare Diagnostics, Erlangen, Germany) and an automatic coagulation analyzer (Sysmex CA-7000, Siemens Healthcare Diagnostics, Erlangen, Germany).	FIBTEM MCF < 8mm predicted hypofibrinogenemia (fibrinogen < 1.28 g/L) with a sensitivity of 82%, a specificity of 90% and AUC of 0.94.	[55]
	A prospective study of 253 patients receiving orthotopic liver transplantation.	Citrated blood samples were collected after induction of general anesthesia, at the end of the hepatectomy, 20 min after graft revascularization, and 90 min after graft revascularization. The blood samples were tested just after collection by ROTEM gamma device operated according to manufacturer instructions and with the type and concentration of reagents as provided by Pentapharm (Munich, Germany). Fibrinogen concentration was measured by the PT-derived method, with values below 2 g/L being checked by the Clauss method.	Sensitivity, specificity and AUC of FIBTEM A10 for detection of plasma fibrinogen level (<1.3 g/L) 86%, 55% and 0.801	[56]
	A retrospective, single-centre, observational study of 243 adult liver transplant patients	Blood samples were collected immediately upon admission to ICU and once daily until the seventh postoperative day. ROTEM tests including EXTEM, INTEM, and FIBTEM were performed. Standard laboratory tests (PT, aPTT, fibrinogen) were performed using a BCS Analyzer (Siemens Healthcare Diagnostics Products GmbH, Erlangen, Germany).	FIBTEM A10/MCF predicted postoperative bleeding with a sensitivity of 90/90%, specificity of 33/32%, AUC of 0.636/0.632, better than fibrinogen concentration with 74%, 39% and 0.531	[66]
	A prospective observational study of 23 patients undergoing orthotopic liver transplantation.	Blood samples were collected after induction of general anaesthesia, during hepatectomy, at the anhepatic stage, 30–60 min after graft revascularization, at the end of surgery, and 24 h after surgery. ROTEM tests (EXTEM, INTEM, FIBTEM and APTEM) were performed in the operating theatre and by the anaesthesiologists treating the patients according to the manufacturer's instructions using equipment and test reagents provided by Pentapharm GmbH. Plasma fibrinogen concentration was determined by the Clauss method performed on ACL Top automates (Instrumentation Laboratory, Lexington, MA, USA).	ROTEM FIBTEM A10 ≤8 mm predicted hypofibrinogenemia (fibrinogen < 1 g/L) with a sensitivity of 0.83, specificity of 0.35, and AUC of 0.61, worse than EXTEM with corresponding values of 0.83, 0.75 and 0.84	[57]
	A retrospective of 401 patients who underwent liver transplantation.	Blood was sampled at 1 h after induction of general anaesthesia, 1 h after surgical incision, 30 min after hepatectomy, and 30 min after graft reperfusion and after hepatic artery anastomosis. A total of 1125 FIBTEM tests were performed according to the manufacturer's instructions. Fibrinogen level was measured using the Dade Thrombin Reagent (Siemens Healthcare Diagnostics) and an automatic coagulation analyser (Sysmex CA-7000, Siemens Healthcare Diagnostics).	ROC curve analysis showed that a cut-off value of FIBTEM A5 at 4 mm and A10 at 5 mm predicted fibrinogen < 1 g/L with a sensitivity of 81% and 76%, specificity of 77% and 82%, AUC of 0.86 and 0.87	[58]
Postpartum hemorrhage	A prospective observational study of 91 women at the third trimester of pregnancy: 37 with postpartum haemorrhage (study group) and 54 without abnormal bleeding.	Standard FIBTEM was carried out by clinicians with citrated blood samples in the delivery room. Plasma fibrinogen was assayed within 5 min after sampling with a STAR automated coagulation analyser (Diagnostica Stago Inc., Franconville, France) according to standard procedures.	A cut-off value of A5 and A15 at 6 mm provided an sensitivity of 100% for both parameters, a specificity of 85 and 88%, and AUC of 0.96 and 0.97, respectively to detect a fibrinogen level <1.5 g/L in postpartum haemorrhage.	[59]
	A prospective observational pilot study including 217 healthy pregnant women	Blood samples were collected upon admission to the delivery room for labor and within 1 h after vaginal delivery. All ROTEM tests were performed with the recommended reagents and in accordance with the manufacturer's procedures. Fibrinogen levels were measured with STA-fibrinogen reagent (Roche Diagnostics GmbH, Mannheim, Germany) using Clauss method.	The AUC of ROTEM FIBTEM MCF for prediction of postpartum hemorrhage defined as blood loss ≥ 500 mL was 0.52 (95% confidence interval 0.41–0.64, p =0.699), similar to the predictive power of fibrinogen levels (AUC=0.53, 95% confidence interval 0.40–0.65, p=0.644).	[67]
Neurosurgery	A prospective observational study of 92 patients undergoing emergent neurosurgery	Blood was sampled in the operating theater on citrated tubes and ROTEM analyses were performed within min of blood sampling by anesthesia nurses or physicians trained to perform the ROTEM tests according to the manufacturer's instructions. Plasma fibrinogen concentration was determined by Clauss method (Siemens-Dade Behring Healthcare Diagnostics, Marburg, Germany).	The need for transfusion (≥ 3 PRBCs) was best predicted by EXTEM and FIBTEM MCF (AUC of 0.72 and 0.71, respectively) and by fibrinogen concentration (AUC of 0.70), with a sensitivity of 38.2, 33.3, 25.6% and specificity of 85.1, 96.2 and 100%.	[60]

AUC=Area under the receiver operating characteristic curve; CI=Confidence Interval; CPB=Cardiopulmonary Bypass; ICU=Intensive Care Unit; ISS=Injury Severity Score