Plasma pool testing
Plasma is the clear, straw-coloured, liquid portion of blood that remains after cellular components are removed. It can be further separated into therapeutic products such as albumin, clotting factors and immunoglobulins.
These proteins are essential for the prevention, management and treatment of life-threatening conditions resulting from trauma, congenital deficiencies, immunologic disorders, or infections.
Plasma is obtained from one of two processes. Source plasma is collected by voluntary donors through a process called plasmapheresis, whereas recovered plasma is collected through whole blood donation which has been separated from its cellular components. These donations are tested for the presence of blood-borne infectious agents such as Hepatitis B, Hepatitis C and Human Immunodeficiency Virus (HIV) by the collection centre.
Manufacturers of therapeutic products then pool plasma from many donors, often hundreds and sometimes up to 10,000, before starting the fractionation process.
To ensure plasma safety and therefore the safety of the final therapeutic product, all plasma pools used for manufacturing of medicinal products must also be tested for the presence of blood-borne infectious agents. This testing is in addition to that carried out by the manufacturer.
An overview of the plasma pool testing process is provided in the diagram below:
What we do
As part of our control testing activities, we conduct Official Control Authority Batch Release (OCABR) testing of plasma pools according to the guidelines set by the European Directorate for the Quality of Medicines (EDQM).
All plasma pools are tested for the presence of:
- Hepatitis B surface antigen (HBsAg) by serological assay
- Human Immunodeficiency viruses types 1 and 2 (HIV 1 and 2) by serological assay
- Hepatitis C virus (HCV) by molecular assay
Dependent on which product the plasma pool is being used to produce, additional tests may also be carried out. These are for the presence of:
- Hepatitis A virus (HAV) by molecular assay
- Hepatitis E virus (HEV) by molecular assay
- Parvovirus B19 (B19V) by molecular assay
We use the most sensitive assay or test available and all of our testing is underpinned by the use of our own NIBSC biological standards and reference materials.
Once the plasma pools have been tested and found free from the presence of blood-borne infectious agents, the pool is certified and the manufacturer may then use this pool to fractionate the various therapeutic proteins. These products may be then sent by manufacturers for testing elsewhere in the Institute.
A manufacturer cannot use a plasma pool without certification from an Official Medicines Control Laboratory (OMCL) such as NIBSC.
The number of plasma pools sent to NIBSC for testing that contain a blood-borne infectious agent is very low indeed. In the last 10 years, NIBSC has tested over 25,000 plasma pools from over 25 million donations and has found only 1 positive pool. This is a positivity rate of about 0.004%. As a matter of course, this pool was destroyed to prevent it from being used any further.
In a regulated and professional environment, fractionated plasma products manufactured by modern processes are among the lowest-risk therapeutic biological products in use today.
If you require more information about plasma pool testing please contact cpb@nibsc.org