Overview

Blood donation is a procedure that can help save lives. People volunteer to donate blood. There are many types of blood donation. Each type helps meet different medical needs.

Whole blood donation

Whole blood donation is the most common type of blood donation. During this donation, you donate about a pint (about half a liter) of whole blood. The blood may stay as whole blood. Or a special machine can separate the blood into its parts. These parts include red blood cells, plasma and platelets.

Apheresis

Apheresis is a type of blood donation where only a certain part of the blood is donated. During apheresis, you are connected to a machine that collects the blood and separates the part needed. After the machine does its work, it returns the other parts of blood back to you. Apheresis is a procedure to collect red cells, plasma or platelets.

  • Platelet donation, also called plateletpheresis, collects mostly platelets. Platelets are the cells that help stop bleeding. Platelets can clump together to form a plug, also called a clot.

    Healthcare professionals may give donated platelets to people whose blood doesn't clot well. Or people who have cancer and don't have enough platelets may receive donated platelets. People who've had organ transplants or surgery where they lost a lot of blood may need platelets too.

  • Double red cell donation allows you to donate two units of red blood cells instead of one unit. Red blood cells give oxygen to the organs and tissues.

    Healthcare professionals may give donated red blood cells to people who've lost a lot of blood. Blood may be given after a person has an injury or accident. Or it may be given to a person who doesn't have enough red blood cells, called anemia.

  • Plasma donation, also called plasmapheresis, collects the liquid part of the blood. This part of the blood is called plasma. Plasma helps blood clot and has proteins called antibodies that help fight off infections.

    Healthcare professionals may give plasma to people who have lost a lot of blood or people who are severely burned. This usually happens after an emergency or bad accident.

Why it's done

In a blood donation, you agree to have blood drawn and collected so that it can be given to someone who needs a blood transfusion.

Millions of people need blood transfusions each year. Some may need blood during surgery. Others depend on it after an accident or because they have a condition that needs certain parts of blood. Blood donation makes this possible. There is no substitute for human blood. All transfusions use blood from donors.

Risks

Blood donation is safe. Healthcare professionals use new, sterile one-time use equipment for each person who gives blood. By doing this, there's no risk of getting an infection by giving blood.

Most healthy adults can safely donate a pint (about half a liter) of blood. Within a few days of giving blood, the body replaces the lost fluids. The body replaces the red blood cells in a few weeks.

How you prepare

Eligibility requirements for blood donation

To be eligible to donate whole blood, plasma or platelets, you must be:

  • In good health and not feeling sick.
  • At least 16 or 17 years old, depending on the law in your state. Some states allow legal minors to donate with parent permission. No upper age limit exists. The rules may vary among individual donor centers.
  • At least 110 pounds (about 50 kilograms).
  • Able to pass the physical and health history evaluations.

Eligibility requirements vary slightly among different types of blood donation.

Food and medicines

Before your blood donation:

  • Get plenty of sleep the night before you plan to donate.
  • Eat a healthy meal before giving blood. Avoid fatty foods, such as hamburgers, fries or ice cream. These high-fat foods may affect how your blood is collected and tested.
  • Drink plenty of water before the blood donation.
  • Avoid drinking alcohol or caffeine before giving blood. Each of these can take away water in your blood, called dehydration.
  • Check to see if any medicines you are taking or you recently took might keep you from donating blood. Avoid aspirin for at least two days before donating blood. Don't donate blood if you are taking antibiotics for an infection. Talk to your healthcare professional before you stop taking any medicines in order to donate blood.
  • Wear a shirt with sleeves that can be rolled up.

What you can expect

Before the procedure

Before your blood donation, a healthcare professional asks you to fill out a form with information about your medical history. The form may ask questions about behaviors known to carry higher risks of infections that can be passed through blood., called bloodborne infections.

Not everyone is eligible to donate blood because of the risk of passing bloodborne infections to others. The following groups are not eligible to donate blood:

  • Anyone who has used injected drugs, steroids or another substance not prescribed by a healthcare professional in the past three months.
  • Anyone who has had a new sexual partner in the past three months and has had anal sex in the past three months.
  • Anyone who has had multiple sexual partners in the past three months and has had anal sex in the past three months.
  • Anyone who has had a positive test for HIV.
  • Anyone who has engaged in sex for money, street drugs or other payment in the past three months.
  • Anyone who, in the past three months, has had close contact with a person who has hepatitis B, hepatitis C or another type of viral hepatitis. Close contact in this case can mean living with or having sexual contact with a person.
  • Anyone who takes oral or injectable post-exposure prophylaxis (PrEP) to prevent HIV.
  • Anyone who has had a rare and severe tick-borne disease called babesiosis in the past two years.

After you complete the form, you have a short physical exam. The exam includes checking blood pressure, pulse, temperature and sometimes weight. A small sample of blood is taken with a finger prick. A healthcare professional then checks the blood sample for the level of the oxygen-carrying part of the blood, called hemoglobin. If the hemoglobin is high enough and you've met all the other screening requirements, you can donate blood.

COVID-19 concerns

The virus that causes coronavirus disease 2019 (COVID-19) hasn't been shown to spread through blood transfusions. But the U.S. Food and Drug Administration (FDA) suggests waiting to donate blood for at least 10 days after a positive diagnostic test for COVID-19 without symptoms. If you have COVID-19 symptoms, avoid giving blood until 10 days after the symptoms have gone away.

During the procedure

During a blood donation, you lie or sit in a reclining chair and extend the arm you want to use for the blood draw on an armrest. A healthcare professional briefly puts a blood pressure cuff or device to stop blood flow, called a tourniquet, around the upper arm. This device helps fill the veins with more blood. This makes the veins easier to see so that the health professional can put the needle in the vein. The blood bag will fill more quickly too.

The healthcare professional cleans the skin and then puts a new, sterile needle in a vein in the arm. This needle is attached to a thin, plastic tube and a blood bag. Once the needle is in place, you tighten your fist many times to help the blood flow from the vein. After the sample pouch fills, more blood flows into the bag to about a pint (about half a liter) level. The needle is usually in place for about 10 minutes when you donate whole blood. When your blood donation is finished, the healthcare professional removes the needle, places a small gauze pad on the needle site and wraps a dressing around your arm.

Apheresis is another common but slightly different way of donating blood. During apheresis, you are connected to a machine that collects and separates different parts of the blood, such as red cells, plasma and platelets. This process allows more of a single part to be collected, and the other parts are given back to the donor. Apheresis donation takes longer than standard blood donation. Sometimes apheresis can take up to two hours. You can read, listen to music, relax or watch videos during an apheresis donation.

After the procedure

After donating blood, you sit in an observation area. You can rest, eat a light snack and drink fluids. After 15 minutes, you can leave. After your blood donation:

  • Drink extra fluids for about 48 hours after donating.
  • Avoid strenuous physical activity or heavy lifting for about 24 hours.
  • If you feel lightheaded, lie down with your feet up until the feeling passes.
  • Keep the bandage wrapped around the arm for the next 2 to 3 hours.
  • If the site bleeds after the bandage is off, put pressure on the site and raise your arm until the bleeding stops.
  • If bruising occurs, apply a cold pack to the area for 20 minutes at a time during the first 24 hours.
  • Consider adding iron-rich foods to your diet to replace the iron lost with blood donation. For example, try beans, nuts, seeds, spinach, broccoli, berries or citrus fruits.

Contact the blood donation center or your healthcare professional if you:

  • Forgot to report any important health information to the blood donation center.
  • Think your blood should not be used for any reason.
  • Have signs and symptoms of an illness, such as a fever, within several days after the blood donation.

Results

Testing

Your donated blood is tested to determine the blood type and Rh factor. It also is tested for antibodies. The blood type is classified as type A, B, AB or O. The Rh factor refers to the presence or absence of a substance that can cause an immune response in the blood, called an antigen. Your blood is Rh positive if you have an antigen called the D antigen. Healthcare professionals can only give donated blood to people with a blood type that is compatible with the donor's blood type and Rh factor. The blood donation organization also tests the blood for antibodies that might cause illness in a person who receives the blood.

People at the blood donation organization send the blood to a special laboratory that tests the blood for infectious conditions. If the tests for infectious conditions are negative, they send the blood out for use. If any tests are positive, the donation center may test the blood again. If the blood test is still positive, someone at the center lets you know. The donation center does not use a blood donation if there is a risk to the person who might receive the blood.

By Mayo Clinic Staff