Evidence-based clinical indications of plasma products and future prospects

Of the human blood that flows through arteries and veins, plasma is the liquid that is most abundantly present and in which the cellular components red cells, leucocytes and platelets are suspended. Fifty-five percent of whole blood is plasma of which 89% water, 2% salts, 3% lipids and 6% proteins. The plasma proteins (60 g/L) consist of 2,000–4,000 different proteins in a concentration ranging from ng/mL (hormones) to ±40 mg/mL (albumin). Each protein constituent has a specific function in the homeostasis of the human body and a lack or a deficiency of a plasma protein might be life-threatening. In a number of clinical pathological situations, plasma proteins are observed as not present or malfunctioning. In others where non-plasma protein laboratory parameters are indicative for the disorder, clinical evidence has shown that plasma protein therapy might be efficacious. Unfortunately, in a number of these diseases and disorders the underlying mechanisms of pathology and treatment are still unknown and the effect of plasma protein therapy can be found only clinically present without or with limited supportive evidence shown by plasma protein laboratory parameters.