What is plasma?

Plasma is the largest single component of blood, and makes up about 55% of total blood volume. It is a clear, straw-coloured liquid, which carries platelets, red and white blood cells.

It contains over 700 proteins and other substances. Once separated from blood cells, plasma can be used in transfusions.

Three bags of fresh frozen plasma thawing before transfusionCollecting plasma from blood and platelet donors

There are two ways we normally collect plasma:

  • by separating it out from whole blood donations
  • from our male A and AB type platelet donors, while they’re donating platelets

Fresh frozen plasma from female donors is not currently used because it is more likely to contain antibodies that could cause a serious reaction when given to a patient.

Some people do not develop antibodies while others do. It is not clearly understood why this happens, but antibodies are more likely to develop after pregnancy.

For this reason, it is safest for patients if we only produce fresh frozen plasma products from male donors.

How plasma is used to save lives

Donated plasma is frozen to preserve its quality and function. This component is known as fresh frozen plasma, or FFP.

FFP can be issued to hospitals or further processed into a more concentrated component that is rich in certain clotting factors called cryoprecipitate.

Plasma transfusions can help the blood to clot and also replace dangerous substances in the patient’s own plasma.Keri in hospital bed bed holds baby Lucy

FFP and cryoprecipitate can be used to help many types of patients – for example people with massive blood loss, liver failure, or rare diseases.

Keri Anglin (pictured) received 22 units of blood, 16 units of fresh frozen plasma, two units of cryoprecipitate and two units of platelets, after a massive bleed while giving birth.

Plasma for medicines

Plasma can also be used for medicines called immunoglobulins.

We collect plasma for medicines from male and female donors from all blood groups.

Currently these medicines are made by pharmaceutical companies and use plasma from donors outside the UK.  

However, we are now able to collect plasma from UK donors to help provide lifesaving and life-enhancing medicines for people who depend on these treatments. More about plasma for medicines