From the Guidelines
Normal fibrinogen levels in adult men typically range from 200 to 400 mg/dL (2.0 to 4.0 g/L). Fibrinogen is a plasma protein produced by the liver that plays a crucial role in blood clotting. During the coagulation process, fibrinogen is converted to fibrin, which forms the mesh-like structure of blood clots.
Key Points to Consider
- Elevated fibrinogen levels (hyperfibrinogenemia) above 400 mg/dL may indicate inflammation, infection, trauma, or cardiovascular disease risk, while levels below 200 mg/dL (hypofibrinogenemia) may suggest liver disease, malnutrition, or certain genetic disorders.
- Fibrinogen levels can be measured through a blood test, typically as part of a coagulation panel.
- Factors that can influence fibrinogen levels include age (levels tend to increase with age), smoking status, obesity, and certain medications like oral contraceptives or estrogen therapy.
- Regular monitoring of fibrinogen levels may be recommended for individuals with clotting disorders, cardiovascular disease risk, or those undergoing certain treatments that affect coagulation.
Clinical Recommendations
- In patients with cirrhosis, a fibrinogen threshold from 100 to 200 mg/dl has been recommended to trigger fibrinogen replacement in the setting of bleeding 1.
- Fibrinogen replacement to achieve fibrinogen levels >200 mg/dl is associated with more effective haemostasis in trauma surgery patients without underlying liver disease 2.
- The use of fibrinogen concentrate or cryoprecipitate is recommended in the management of bleeding and coagulopathy following major trauma, with an initial dose of 3 to 4 g or 50 mg/kg of cryoprecipitate 2, 3.
Considerations for Fibrinogen Replacement
- Fibrinogen production and degradation in patients with decompensated cirrhosis remains poorly understood, and low levels of fibrinogen may reflect advancing hepatic synthetic dysfunction rather than a direct involvement in the pathophysiology of bleeding 1.
- The presence of VWF in cryoprecipitate may pose a thrombotic risk in patients with cirrhosis, and fibrinogen concentrate may be preferred due to its lower volume and lack of need for cross-matching 1.
From the Research
Fibrinogen Levels in Men
- Fibrinogen plays a central role in coagulation, and low fibrinogen levels have been found to be risk factors for exaggerated bleeding, transfusion needs, and adverse outcomes 4
- Normal plasma fibrinogen levels range from 2.0 to 4.5 g/L, and current guidelines recommend maintaining the plasma fibrinogen level above 1.5 g/L 5
Thresholds for Fibrinogen Administration
- A low fibrinogen can be a low plasma concentration or a low functional fibrinogen as assessed by point-of-care techniques such as thromboelastography (TEG) or thromboelastometry (ROTEM) 4
- Algorithm-based individualized goal-directed use of fibrinogen resulted in highly significant reduction in transfusion needs, adverse outcomes, and mortality 4
Fibrinogen Replacement Therapy
- Fibrinogen replacement therapy with cryoprecipitate or fibrinogen concentrate can reduce the incidence of major bleeding in patients with hypofibrinogenemia during cardiopulmonary bypass in thoracic aortic surgery 6
- Fibrinogen concentrate supplementation and partial FFP replacement can both maintain fibrinogen levels > 1 g/L after therapeutic plasma exchange, but modest differences in classical coagulation tests and bedside ROTEM tests favor FFP replacement 7
Comparison of Fibrinogen Concentrates
- The choice of fibrinogen concentrate can influence the stability of a clot in vivo, and different concentrates have variable constituents that can affect clot formation and lysis 8
- Fibrinogen concentrate represents an important option for the treatment of coagulopathic bleeding, and further studies are needed to determine precise dosing strategies and thresholds for fibrinogen supplementation 5