What Is Plasma?

You may have heard of red blood cells, white blood cells, and platelets. But there’s something else in your blood: plasma.

It’s the liquid part of your blood. One of its jobs is keeping your blood pressure in a healthy range. It also carries important proteins, minerals, nutrients, and hormones to the right places in your body.

Plasma makes up the biggest part of your blood: about 55%. Even though blood appears red when you see it outside the body, plasma itself is a pale yellow color.

What’s In Plasma, And What Does It Do?

Plasma is made up of about 90% water. It also contains salts and enzymes. And it has antibodies that help fight infection, plus proteins called albumin and fibrinogen.

Plasma helps carry proteins, hormones, and nutrients to different cells in your body. These include growth hormones that help your muscles and bones grow, as well as clotting factors that help you stop bleeding when you get a cut.

Some of the nutrients it helps deliver are minerals like potassium and sodium. These help your cells work.

Plasma helps your body maintain normal blood pressure and blood volume levels. It also gets rid of the chemical waste from cells. It does this by dissolving the substances the cells don’t need and carrying them away.

Why Donate Plasma?

Doctors can use plasma to help treat different kinds of serious health problems.

Some of the elements in plasma, including the antibodies and chemicals that help your blood to clot, can help in medical emergencies like burns and trauma.

Other things that plasma donation are good for include:

  • Developing treatments. The antibodies and proteins can also be used to develop treatments for rare diseases, including some immune system problems.
  • Cancer. Adults and children with different kinds of cancer -- including leukemia -- sometimes need plasma transfusions.
  • Transplant surgery. Some people who get liver or bone marrow transplants need plasma.
  • Hemophilia. In this rare disorder, a person’s blood doesn’t have enough clotting factors, so donated plasma can help.


Donating It

To donate plasma, you have to be at least 18 years old and weigh at least 110 pounds. You’ll need to get a physical examination and get tested for certain viruses like HIV and hepatitis.

Donating plasma is a little different from donating whole blood. When you donate whole blood, it goes straight into a collection bag and is later separated in a lab. When you donate plasma, the blood that’s drawn from your arm goes through a special machine to separate the different parts of your blood.

The parts that are left over, including your red blood cells, go back in your body, along with some saline (salt water) solution. The process usually takes about 1 hour and 15 minutes.

 If you have type AB blood , it is a “universal recipient .” This means they can receive blood from any blood type.   Type O has no antibodies against blood types and are considered a 'universal donor' , almost anyone can receive this blood type during a transfusion. 

WebMD Medical Reference Reviewed by Jennifer Robinson, MD on February 24, 2020



American Red Cross: “Blood Plasma.”

DonatingPlasma.org: “What is Plasma?”

University of Rochester Medical Center: “What is Plasma?”

KidsHealth.org: “What’s Blood?”

The Blood Center: “Plasma Facts.”

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