Coagulation Assessment and Fibrinogen Thresholds in Therapeutic Plasma Exchange-A Narrative Review.

Many therapeutic apheresis procedures that remove plasma or plasma components also lower coagulation factor levels, which can increase patients' bleeding risk. In this narrative review, we sum up data on clotting factor removal and the development of dilutional coagulopathy mostly associated with therapeutic plasma exchange (TPE) treatment and consider available tests for coagulation assessment. It is common in clinical practice to check fibrinogen levels regularly during repetitive TPE treatments and use it as a marker of hemostasis because of its long half-life and central role in hemostasis. We discuss the background of current clinical practice regarding fibrinogen thresholds discuss different threshold levels and data on the associated risk of bleeding. We stress the importance of additional bleeding risk assessment when patients are exposed to concomitant invasive procedures. We also describe the possibilities for fibrinogen replacement during TPE treatments with either fresh frozen plasma or fibrinogen concentrate and the associated effect on factor XIII levels. Finally, we briefly discuss alternative apheresis procedures regarding their fibrinogen-sparing potential.