What is blood donation?

Blood Donation
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Blood donation: Overview

Blood donation means giving some of your blood so that it can be used to help someone else. Donated blood helps people who have lost blood in an accident. It also helps people who have an illness such as cancer, anemia, sickle cell disease, or hemophilia.

If you donate blood before you have surgery, your own blood will be kept for you in case you need a blood transfusion. If you don't need it, your blood may be donated to someone else.

Donated blood includes red blood cells and the other things that make up the blood, such as platelets and plasma. Blood that contains all the parts is called whole blood.

You can donate blood at American Red Cross clinics or other clinics or blood banks. You may be able to donate during blood drives at your workplace.

When you donate whole blood, you give about 1 pint (473 mL) . It takes about 10 minutes. The whole process—including answering questions and having a short exam—takes up to an hour.

Donated blood is tested to make sure that it's safe to use. It's also checked for its type. This makes sure that the person who needs blood gets the right type.

How do you prepare for donating blood?

You can do a few things before you give blood to make sure that you have a good experience:

  • Make sure you feel good. Don't give blood if you feel ill.
  • Eat foods rich in iron, such as meat, fish, beans, or leafy green vegetables, a few days before you donate.
  • Eat a healthy meal. But avoid fatty foods. They can affect some of the tests done on donated blood to make sure it's safe.
  • Drink plenty of fluids, especially the day before you donate.
  • Get plenty of sleep the night before.
  • Plan to wear a shirt with sleeves that you can roll up above your elbows.

What are the risks of donating blood?

Donating blood is safe. You cannot get HIV from donating blood. The needle and bag used to collect blood are sterile and prepackaged. A new package is used every time.

You may have a small bruise on your arm. In rare cases, a person's arm may bleed after the bandage is taken off. If this happens, raise your arm and put pressure on the needle site for several minutes.

Some people may feel faint after they donate blood. This may happen for younger people and for people who are donating for the first time. If you have fainted after donating blood and you choose to donate again, be sure to tell the person who is going to draw your blood. Drinking extra water before you donate may reduce this risk.

How can you trust that donated blood is safe?

The U.S. Food and Drug Administration (FDA) enforces five ways to protect donated blood from disease.

Donor screening.

To donate blood, you must answer questions about your health, your travel, and any behavior that increases your risk for certain diseases. To be sure you are in good health to donate, your temperature, blood pressure, and the protein in your red blood cells (hemoglobin) are checked.

Deferred-donor lists.

Organizations that collect blood keep lists of people who are permanently prevented from giving blood because of certain types of disease. Donors are checked against this list.

Blood testing.

After donation, every unit of blood is tested for certain diseases. If disease is found, the blood is thrown away.


Donated blood is isolated from other blood. It can't be used until it passes all tests.

Quality assurance.

Blood centers must keep careful records of donated blood. If there's a problem, the center must tell the FDA.

Who can donate blood?

To donate blood, you must:

  • Be at least 17 years old. (In some states, you can donate if you are 16 years old and get permission from a parent.)
  • Weigh at least 110 lb (50 kg). If you are under 18 years old, you may need to meet a certain height and weight measurement.
  • Be in good health.

Some people can't donate because of health or other issues. For example, you may not be able to donate if:

  • You recently donated blood or a blood product. The length of time you must wait between donations depends on the product you are donating, such as whole blood or platelets.
  • You don't have enough hemoglobin in your blood. Before you donate, you will have a test to check your hemoglobin level.
  • You are pregnant.
  • You have traveled to certain countries.
  • Your blood pressure is too high or too low. Your blood pressure will be checked before you donate.
  • You take certain medicines.
  • You have certain health problems, such as HIV.
  • You had a recent needlestick or got a tattoo or piercing.

Having a long-term illness, such as diabetes, doesn't mean you can't donate. You may be able to give blood if your health problem is under control. But you shouldn't donate blood if you feel like you're getting a cold or the flu.

Before you donate, a health professional will ask about your current and past health to make sure that you can donate. Some of these questions are very personal, so you will be asked them in private. You will be asked these questions every time you give blood, because the list of who can give blood may change, or your health may change.

Your body will replace the lost fluid in 24 hours. (It takes a few weeks to replace red blood cells.) You will have to wait 56 days before you can give whole blood again.

Blood draw for donation or treatment: When to call

Call your doctor now or seek immediate medical care if:

  • You are dizzy or lightheaded or feel like you may faint.
  • You have signs of infection, such as:
    • Increased pain, swelling, warmth, or redness.
    • Red streaks leading from the area.
    • Pus draining from the area.
    • A fever.

Watch closely for changes in your health, and be sure to contact your doctor if you have any problems.

How is blood donation done?

You will fill out some forms and answer questions about your health.

A health professional will measure your temperature, pulse, and blood pressure. They also will use a finger-stick test to make sure that you have enough hemoglobin in your blood.

The health professional will clean the arm you will use to give blood. Then they will put a needle into a vein on the inside of your elbow. The needle is attached to a bag to collect the blood. You will probably feel a quick pinch when the needle goes in.

You may be given a soft ball or another object to squeeze every few seconds to help the blood flow.

When the bag is full, the health professional will take out the needle. You will get a bandage wrapped around your arm to stop any bleeding.

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