Blood 101 (All about blood)
Blood is life. It’s the amazing fluid that keeps us alive; it’s the amazing gift we give to others to help them heal and live. Each and every day, patients in more than 50 local hospitals served by BloodCenter of Wisconsin need approximately 800 units of blood. You may not always see their faces, but the adults and children you help with your gift of blood are very real.
About Blood
Blood is unique. It is made up of four components: red cells, platelets, white cells and plasma. When you donate “whole blood,” you provide all of these components. However, when you make a component donation, also called an apheresis (a-fur-EE-sis) donation, you donate one or more of these specific components and receive back “the rest” of your blood. Apheresis donations are generally better for patients because patients can receive the blood cells or products they need, from a smaller number of donors, reducing the likelihood of an adverse reaction. Each blood component has a special purpose:
Red cells
Red cells are made in bone marrow. They contain a protein called hemoglobin that attaches to oxygen and allows it to be transported to all body tissues. Red cells are what give blood its red color. There are about a billion red cells in two or three drops of blood. Without enough red cells, you would become very weak. Red cells carry oxygen and can be needed by many different patients including:
  • Patients with sickle cell disease
  • Premature babies
  • Patients experiencing post-surgical complications
Platelets are made in bone marrow and help your blood to clot. They help heal the cuts we can see, and the damage to the blood vessels inside our bodies that we can’t see. Without enough platelets, you would risk bleeding internally and being unable to stop any external cuts from bleeding. Platelets help blood clot and can be needed by many different patients including people:
  • Having heart surgery
  • Experiencing uncontrolled bleeding
  • Going through chemotherapy
Plasma is the fluid portion of blood. It contains proteins and salts, and it helps to carry not only blood cells, but also enzymes, hormones and nutrients. It also affects your blood pressure. Without sufficient amounts of plasma, important blood cells would not be able to circulate throughout your body. Plasma carries nutrients and cells throughout your body. Plasma can be needed by many different patients including burn victims, those with liver disease or hemophilia.
White cells
White cells are made in bone marrow and help you to fight disease. Without enough white cells, you wouldn’t be able to battle off disease –– even the common cold.
Blood facts
  • Summer and holiday donations decrease by 20%.
  • Every three seconds, someone in the United States needs blood. There is no substitute.
  • BloodCenter of Wisconsin strives to see 800 donors a day, 6 days a week, to collect the blood needed by patients in more than 50 hospitals with which we partner.
  • The average adult has about 10 to 11 pints of blood. During a whole blood donation, about one pint is drawn.
  • A unit of whole blood can impact the lives of up to three people because it can be separated into three distinct products, each of which has a different function and can be used in concentrated doses depending on patient need.
  • In order to donate blood you must weigh at least 110 lbs. and be in general good health.
  • You must be at least 17 years old (16 with signed parental consent).
  • Less than 5% of the eligible population donates.
  • One in three people will need a blood transfusion in his/her lifetime.
  • Someone in our area receives a blood transfusion every four minutes.
  • You are eligible to donate whole blood again 56 days after your donation.
  • People with O negative blood type are universal donors. This means their red blood cells can be transfused to patients with any blood type.

Take this quiz to test your knowledge about blood»

What is Your Blood Type?
Do you know what blood type you have? It will fall into one of eight blood types.
No matter which blood type you have, your blood is critically important and helps save lives. After you donate for the first time, you may also find that you’re a rare blood type donor. A person with a rare blood type does not have better or worse blood — it’s just a genetic difference which means that your donation may be someone’s only hope for survival.
Blood types
Your blood type is determined by the presence of specific molecules or antigens found on the surface of red blood cells. There are four main blood types: O, A, B and AB. Your blood also carries an Rh factor that is positive or negative. Together, that gives us 8 possible blood variations: O-, O+, A-, A+, B-, B+, AB- and AB+.
If you have O negative blood you have a special gift. About 8% of the population has O negative blood or the universal blood type. If you have this universal blood type you can save 100% of the population because your blood can save a person who has ANY blood type.

What it means to be a rare donor
If you received a letter from BloodCenter of Wisconsin asking you to register with the American Rare Donor Program (ARDP), you have been identified as a rare blood donor. You could potentially be a match for a patient in need. People with rare blood types often need blood to help treat life-threatening conditions such as cancer, sickle cell disease, heart disease, lupus and other disorders. These patients depend on donors like you.
Q: What does it mean to have a rare blood type?
A: The term “rare” means that the type occurs in only a few people. Some rare types only occur in 1 in 5,000 people. Many rare types are unique to specific populations. For example, Vel negative blood is more common in Caucasians while U negative blood is more commonly found in African Americans.
Q: Does this mean there is something wrong with my blood?
A: No. A person with a rare blood type does not have better or worse blood — it is just a genetic difference. And it means you are extremely special!
Q: If it is a genetic difference, does that mean others in my family might also be rare?
A: Yes, especially your brothers and sisters. Please encourage them to donate also.
Q: Why are rare donors needed?
A: Because some blood types are so rare, your donation may be someone’s only hope for survival. Patients who need frequent transfusions because of certain diseases such as sickle cell disease, leukemia and other cancers are especially at risk.
Q: What is ARDP?
A: ARDP is the American Rare Donor Program. It is based in Philadelphia where they maintain a nationwide database of rare donors.
Q: What happens when I give permission to be an ARDP registered donor?
A: BloodCenter of Wisconsin will notify ARDP that we are registering a donor, for example, that is O Positive and U Negative. If another blood center needs O Positive U Negative blood, ARDP can check their database and see that we have a donor registered with that type. They will then contact BloodCenter to see if we have blood available or can call a donor to donate.
Q: Will I ever be contacted by ARDP?
A: No. BloodCenter of Wisconsin only provides ARDP with your blood type and donor number. No personal information is provided.
Q: What happens after I join ARDP?
A: BloodCenter of Wisconsin will contact you occasionally to update your address. We may also contact you to donate if we get a request for your rare type and have no units available in inventory.
Q: Can I continue to donate regularly or should I wait until my type is needed?
A: Please continue to donate regularly. We get many requests each day for patients across the country that are in immediate need of blood. If we have blood available in our inventory, we can ship it the same day.
Q: What if I donate and my type isn’t needed?
A: If you donate blood and we do not have any requests for your type, your donation is frozen for use in the future. Blood can be specially frozen for up to 10 years.
Q: What if I have a question about the letter I received or about being a rare donor?
A: A BloodCenter of Wisconsin staff member will be glad to help you, please call (414) 937-6205.

Blood Safety and Testing
BloodCenter of Wisconsin is committed to safety — for our donors, our recipients and our employees.
Is donating blood safe?
Donating blood is completely safe. You cannot contract any diseases from donating blood. A sterile kit is used once and thrown away. BloodCenter of Wisconsin is committed to the safety and comfort of donors.
What happens to my blood after it’s donated?
After your blood is collected, it is sent to BloodCenter of Wisconsin’s labs for testing. It is required by the Food and Drug Administration (FDA) that all blood undergo a series of lab tests before it is given to patients. We perform 14 separate tests on blood. These include tests for sexually transmitted diseases, West Nile virus, hepatitis and other illnesses. If a unit of blood passes all of these tests, it is determined safe for distribution.
What tests are performed on donated blood?
The specific tests currently performed include:
  • ABO Rh
  • Hepatitis B surface antigen (HBsAg)
  • Hepatitis B core antibody (anti-HBc)
  • Hepatitis C virus antibody (anti-HCV)
  • HIV-1 and HIV-2 antibody (anti-HIV-1 and anti-HIV-2)
  • HTLV-I and HTLV-II antibody (anti-HTLV-I and anti-HTLV-II)
  • Serologic test for syphilis
  • Nucleic acid amplification testing (NAT) for HIV-1, HCV, HBV and WNV
  • Antibody test for Trypanosoma cruzi, the agent of Chagas' disease
How is blood stored and used?
Each unit of whole blood normally is separated into several components. Red blood cells may be stored under refrigeration for a maximum of 42 days, or they may be frozen for up to 10 years. Red cells carry oxygen and are used to treat anemia or blood loss. Platelets are important in the control of bleeding and are generally used in patients with leukemia and other forms of cancer. Platelets are stored at room temperature and may be kept for a maximum of five days. Plasma can be stored frozen for a year before being thawed and transfused. Plasma serves as a source of plasma proteins for patients who are deficient in or have defective plasma proteins. Plasma is generally used to manage preoperative or bleeding patients who require replacement of multiple plasma coagulation factors.
Cryoprecipitated AHF, which contains only a few specific clotting factors, is made from fresh frozen plasma and may be stored frozen for up to one year. Granulocytes are sometimes used to fight infections, although their efficacy is not well established. They must be transfused within 24 hours of donation.
Other products manufactured from blood include albumin, immune globulin, specific immune globulins, and clotting factor concentrates. Commercial manufacturers commonly produce these blood products from blood donations.

How is Donated Blood Used?
After your blood is collected, it is sent to BloodCenter of Wisconsin’s labs for testing. It is required by the Food and Drug Administration (FDA) that all blood undergo a series of lab tests before it is given to patients. If a unit of blood passes all of these tests, it is safe for distribution.
Thanks to our volunteer blood donors, BloodCenter is able to provide patients with red cells, platelets and plasma products. Some plasma derived from whole blood donations is used for products that are not used directly for patient care but are used for important research.
Blood donation
  • Donor registers.
  • Health history and “mini physical” are completed.
  • About 1 pint of blood and several small test tubes are collected from each donor.
  • The bag, test tubes and the donor record are labeled with an identical bar code label to keep track of the donation.
  • The donation is stored in iced coolers until it is transported to a BloodCenter location.
Blood processing
  • Donated blood is scanned into a computer database.
  • Most blood is spun in centrifuges to separate the transfusable components — red cells, platelets, and plasma.
  •  The primary components like plasma can be further manufactured into components such as cryoprecipitate.
  • Red cells are then leuko-reduced.
  • Single donor platelets are leuko-reduced and bacterially tested.
  • Test tubes are sent for testing.
Blood testing
Steps 2 and 3 take place in parallel:
  • The test tubes are received in our laboratories.
  • 14 tests are performed on each unit of donated blood to establish the blood type and test for infectious diseases.
  • Test results are transferred electronically to BloodCenter within 24 hours.
  • If a test result is positive, the unit is discarded and the donor is notified. Test results are confidential and are only shared with the donor, except as may be required by law.
Blood storage
  • When test results are received, units suitable for transfusion are labeled and stored.
  • Red cells are stored in refrigerators at 42.8ºF for up to 42 days.
  • Platelets are stored at room temperature in agitators for up to 5 days.
  • Plasma and cryoprecipitate are frozen and stored in freezers for up to one year.
Blood distribution
Blood is available to be shipped to hospitals 24 hours a day, 7 days a week.

Glossary of Terms Used in Blood Donation This glossary of commonly used terms is just one of the resources BloodCenter has created to help you understand the process of blood donation.
Red blood cells carry oxygen throughout the body. Anemia is a shortage of red blood cells in the blood.
Apheresis (a-fur-E-sis) is the term used for the collection of blood components: platelets, plasma and/or red cells. White cells are typically not collected because they are rarely transfused.
Bone Marrow
Bone marrow is the soft tissue located inside bones. Bone marrow produces blood cells: red cells, plasma and platelets.
Hemophilia (hem-o-FEEL-e-a) is an inherited disease in which a particular clotting factor is missing. This means that when people with hemophilia receive an injury that breaks the skin, it takes longer for their body to stop the bleeding and start healing. For more information about hemophilia, go to our Bleeding & Clotting Disorders section.
Idiopathic Thrombocytopenic Purpura (ITP)
Idiopathic thrombocytopenic purpura (ITP) (id-ee-o-PATH-ic throm-bo-cy-to-PE-nic pur-PUR-a) is a bleeding disorder in which the blood does not clot as it should. This is due to too few platelets. A symptom of ITP is frequent bruising of the skin. For more information on ITP, check out the National Heart, Lung, and Blood Institute website.
Platelets are one of the components of blood, along with plasma, red cells and white cells. Platelets, or thrombocytes (THROM-bo-sites), are made in bone marrow. They circulate through blood vessels and help stop bleeding by sticking together to seal small cuts or breaks in blood vessels.
Plasma is the liquid portion of blood. One pint of blood contains about half a pint of plasma. Plasma is composed of proteins and salts and impacts blood pressure.
Red Cells
Red cells are one of the components of blood along with platelets, plasma and white cells. Red cells carry oxygen to all parts of the body. An insufficient amount of red cells can result in anemia.
Sickle Cell Disease
Sickle cell anemia is an inherited blood disease that affects red blood cells. Normal red blood cells are smooth and round. In sickle cell anemia, the red blood cells become hard, sticky, and shaped like sickles or crescents. Their shape causes them to block the flow of blood in blood vessels. Resulting symptoms can include joint pain, headaches and anemia. Persons with sickle cell disease can require frequent transfusions. For more information on sickle cell disease, go to the National Heart, Lung, and Blood Institute website.
A transfusion is the introduction of blood or blood components (platelets, plasma or red blood cells) directly into the bloodstream. It is the process by which patients receive donors’ blood.
White Cells
White cells are one of the components of blood, along with platelets, plasma and red cells. White cells or leukocytes (LUKE-o-sites) help the body to fight infection.
von Willebrand Disease (VWD)
VWD is a bleeding disorder which can be inherited from either parent. It affects all ethnic groups , and is the most common bleeding disorder. The disease can be mild to severe, and symptoms vary. Symptoms include nosebleeds, easy bruising, heavy menstrual periods, and prolonged bleeding after surgery, childbirth, or injury.

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