Guide for the Assessment of Clotting Factor Concentrates

Plasma qualityFactors which have an impact on plasma quality and safety include:1) Plasma handling factors such as separation, storage, and transport, which also depend onthe methods used for collecting plasma (recovered from whole blood or obtained byplasmapheresis)2) Donor epidemiology (viral infection, prion disease)3) Donor selection and testing procedures (including NAT) to reduce the window period forinfection with different virusesAll these factors affect the safety of fractionated plasma products with respect to transmissible infectiousagents. They also affect the yield and specific activity of products.Donor selectionDonor selection procedures are designed to identify and exclude donors at risk of being infected withviruses that can be transmitted by blood transfusion. In developed countries, donor selection procedureshave reached a high level of sophistication and complexity, and regulators have included these proceduresin their assessment of overall safety of material used to manufacture plasma products.Exclusion criteria for donors used in different regulatory climates include:• History of blood-borne infections• Intravenous drug use• High risk sexual behaviour (male-to-male sex, prostitution)• Having received blood, tissues, etc.• Risky behaviour (tattoos, piercing, etc.)• Medical procedures, such as certain illnesses, surgery etc.Like all the measures described in this guide, the ability of different countries to implement thesemeasures may vary. Each regulatory authority must assess a country’s local needs before mandatingspecific measures.Plasma typesPlasma types may be distinguished based on donor remuneration status (paid or unpaid) and methodof collection (recovered or source plasma). Recovered plasma is a by-product of donated whole bloodand is generally procured from unpaid donors. Source plasma is collected from donors, most of whomare paid, through a process known as plasmapheresis, which removes only the donor’s plasma. Whencollected and processed with steps that exclude and inactivate or eliminate enveloped viruses (HIV,HCV, and HBV), both recovered and source plasma have the same level of viral safety in the derivedproducts.In the past, before the introduction of regulation in the blood sector, plasma for fractionation frompaid donors was considered to be of higher risk of viral infection than plasma from voluntary donorsdrawn from the same population. However, nowadays, in the developed blood systems of North Americaand Europe, this is no longer the case. This is the result of the strict regulatory regimens found in theseareas and the introduction of similarly strict industry standards. The inclusion of nucleic acid testing(NAT) for plasma for fractionation in these systems has greatly reduced the viral load for HIV andHCV for all donor types. This equivalence in safety is not necessarily the case in other donor populations,4 Guide for the Assessment of Clotting Factor Concentrates