Over half of our blood consists of a yellow liquid called plasma. Plasma surrounds our blood cells and transports them around the body.
Plasma plays a very important role in providing fluid storage for the body, maintaining blood pressure and preventing blood vessels from collapsing. It also helps to cool and warm the body.
What is plasma?
Plasma is made mainly from water. It contains proteins such as:
- albumin, which is beneficial to people with severe burns, or those who have experienced substantial loss of blood,
- clotting substances, which help to control bleeding, and
- antibodies, which help fight infection and are used to fight diseases, such as tetanus, hepatitis and rabies.
Plasma also contains:
- hormones,
- minerals,
- salts,
- vitamins,
- fats, and
- sugars.
What is plasma used for?
Many of these components can be extracted from plasma to be used for specific purposes. For example, plasma is the source of anti-D, a substance given to pregnant women who have the blood factor Rhesus negative if they are carrying Rhesus positive babies. This prevents potentially fatal complications.
Fresh frozen plasma is prepared from the liquid that floats on the surface after separation of donated whole blood. Plasma is frozen as soon as possible, and not more than eight hours after donation. Most plasma products are manufactured from pools of plasma that are made up of many thousands of blood donations.
Sometimes, plasma is obtained through a process called plasmapheresis, or plasma exchange. In this process the plasma is separated out before the rest of the blood is returned to the donor.
Before they are able to donate blood, all blood donors have to adhere to a strict set of guidelines about their health history. In addition, blood products are treated to remove any possibility of viruses existing in the liquid.
Since the end of 1999, all plasma used as a source for plasma products in the UK has been sourced from the US. This is because of a small, unconfirmed risk that variant Creutzfeldt-Jakob disease (vCJD) may be transmitted in certain types of plasma products.
Glossary
- Blood
- Blood supplies oxygen to the body and removes carbon dioxide. It is pumped around the body by the heart.
- Plasma
- Plasma is the liquid part of blood, which holds other blood cells together.
- Blood vessel
- Blood vessels are the tubes in which blood travels to and from parts of the body. The three main types of blood vessels are veins, arteries and capillaries.
- Disease
- A disease is an illness or condition that interferes with normal body functions.
- Blood donation
- Blood donation is volunteering to give some of your blood to help people who need extra blood after or during surgery.