Final answer:
Fibrinogen, crucial for blood clotting, typically has a clinical level of 200-450 mg/dL. Exact fibrinogen levels post-blood loss can vary and are not specified in the provided references.
Step-by-step explanation:
After a significant blood loss, levels of plasma proteins such as fibrinogen can drop. Fibrinogen is essential for blood clotting as it is converted to fibrin during coagulation, forming a mesh that traps platelets and erythrocytes to produce a clot. Normal clinical levels of fibrinogen are 0.2-0.45 g/dL blood, which is equivalent to 200-450 mg/dL. When blood loss occurs, the fibrinogen level can decrease. However, the specific point at which fibrinogen levels would typically reach less than 100 mg/dL is not provided in the reference materials, and it can be variable depending on the individual's response to blood loss and compensatory mechanisms.