What You Need to Know About Donating Blood

by Lauren Steele

According to the Red Cross, someone in the U.S. needs blood every two seconds. That’s part of the reason the organization has marked January as National Blood Donor Month. Winter is typically one of the hardest times to get people to donate blood and platelets. And patients are still in need in winter.

Because blood cannot be manufactured, patients who rely on whole blood, red cells, platelets, and plasma also rely on donors. That’s why donation is important year-round.

Whether you’ve been donating for years, you’re donating for the first time, or you’ve never donated before, we’ve gathered all of the information and insights you need to know about being a blood donor, as well as how donating blood works. 

Blood types

Your blood type is determined genetically. The four main blood groups (A, B, AB, and O) and the Rh group (which determines a blood type as “positive” or “negative” combine to make the eight most common blood types: A+, A-, B+, B-, AB+, AB-, O+, and O-. 

Not all blood types are compatible with each other, but O- red blood cells are considered universal. This blood type is often used in emergency situations where life-saving transfusion is required prior to completion of a blood donor match test. However, AB type blood is considered universal for plasma transfusion. 

In the U.S., O- is the most rare type of blood. According to the Stanford Blood Center, only about 6.6% of the population has O- blood. The most in-demand type of blood is O+, because it is the most frequently occurring blood type. In the U.S., 37% of the population has O+ blood.

The parts of your blood

Blood is composed of four components: red blood cells, white blood cells, platelets, and plasma—and each of these four components can be donated. 

• Red blood cells carry hemoglobin (which gives them their red color). They carry oxygen from the lungs to the tissues and organs before picking up carbon dioxide from the tissues and organs transporting them for removal from the lungs. Red blood cells must be used within 42 days of donation, according to the Red Cross. The average red blood cell transfusion is approximately 3 units, aka one pint.

• White blood cells, called granulocytes, help the body fight infection. According to the U.S. National Library of Medicine, chemotherapy patients or those who have had bone marrow transplants may have low white blood cells, and transfusions of white blood cells can help improve these patients’ ability to fight infection.

• Platelets are small cell fragments that help stop bleeding by sticking together and forming a clot. Donating platelets can help save cancer patients undergoing chemotherapy, patients with major injuries that resulted in massive blood loss, and patients with blood disorders (such as Sickle cell disease) or who have undergone transplants. Platelets must be used within 5 days of donation.

• Plasma brings nutrients like proteins, minerals, vitamins, sugars, and fats to all parts of the body and carries away waste products. In transfusion medications, proteins such as albumin, immunoglobulin, and clotting factors are isolated from plasma using a fractionation process. Once isolated and fractionized, those proteins can be stored freeze-dried (lyophilized) for long periods of time and be used to treat specific medical conditions, such as CVID.

How donating blood works

On the day of your donation, you will register and be asked to show ID. After, you will complete a Health History document have your blood pressure, temperature, and pulse checked. 

According to Red Cross averages, the entire process of donating blood takes about one hour and 15 minutes—while the actual donation of a pint of whole blood unit takes only eight to 10 minutes. You can do whole blood donation, plasma donation, platelet donation, or Power Red donations, which allows you to donate two units of red blood cells while returning plasma and platelets to you.

For the donation, a medical professional will clean the insertion site and insert a sterile needle in your arm. For most people, this just feels like a small pinch. After your donation is collected, most donation centers and blood drives have free snacks and refreshments you can enjoy while recovering from the donation.

Remaining healthy after donating blood means taking adequate time between donations. The Red Cross requires that donors wait at least eight weeks between donations of whole blood and 16 weeks between Power Red donations. Platelet donors may give every 7 days up to 24 times per year.

The Red Cross recommends that you drink an extra 16 oz. of water (or other nonalcoholic drink) and eat a healthy meal, avoiding fatty foods like hamburgers, fries or ice cream before your donation appointment. You also shouldn’t take aspirin for two days prior to donating blood platelets.

Interested in donating blood? Find a local Red Cross blood drive near you here.