Plasma is the clear, straw-coloured, liquid portion of blood that remains after cellular components are removed. It is separated into therapeutic products such as albumin, clotting factors and immunoglobulins.
Plasma pools are made from a number of mixed individual donations – either from source plasma, recovered plasma or a mixture of both. Source plasma is collected from voluntary donors through a process called plasmapheresis.
Recovered plasma is collected through whole blood donation which has been separated from its cellular components. Plasma pools may contain over 10 000 individual donations.Figure A: a testing algorithm
Our section at NIBSC oversees the routine testing of plasma pools by whatever techniques are required. We coordinate the development of systems and methods as the field evolves and apply them reliably to testing.
We carry out these tests as part of NIBSC’s commitment to the European Official Medicines Control Network (OMCL).
As viral infections can be transmitted by blood and medical products derived from blood, each donation undergoes testing for the presence of multiple infectious disease markers. We then independently test the plasma pools.
NIBSC currently tests all plasma pools for the presence of:
Some pools are also tested for the presence of Hepatitis A virus (HAV) and parvovirus B19 (B19) by molecular assay.
We upgrade or replace tests with more sensitive technologies as these become available, and all tests are underpinned by biological standards and reference materials.
There are specific testing requirements laid down by the European Pharmacopoeia and, as new pathogens emerge, we modify our testing to take this into account. For example, Hepatitis E virus may be contaminating plasma-derived products, and the European Directorate for the Quality of Medicines (EDQM) group for the safety of plasma-derived products is looking into this.
Once plasma pools are certified, they are subjected to a number of different processes and treatments before the various therapeutic proteins are separated out by fractionation. These products are sent by manufacturers for testing elsewhere in the institute.
Manufacturers cannot release any products until an OMCL certifies the plasma.
Control authority certification of approval is performed within the framework of control authority batch release of medicinal products derived from human blood and plasma and follows the current Guideline on EU Administrative Procedure for Official Control Authority Batch Release.
The group currently carries out research as part of its general duties. This includes practical areas of study such as investigating new formulations for freeze-drying and investigating increasing the shelf-life of products without affecting potency.
We constantly seek newer, more sensitive and more accurate assays for plasma pool testing. We keep a watching brief on all areas of technological development to implement state-of-the-art techniques as needed. Our group is at the forefront of the new digital PCR technology.
Because we have a massive sample archive at NIBSC stretching back nearly 25 years, we are well-placed to look at the rise of new disease-causing agents such as Hepatitis E virus.
Dr Rob Anderson, Principal ScientistDr Kathryn Doris, Senior ScientistMr David Padley, Senior ScientistMr Josh Duran, ScientistMr Francis Phimister, Scientist