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Facts about Blood
(Information provided by the American Association of Blood Banks)

Blood Types and Breakdown of Population by Percentage
 

O+ 38%	O- 7%
A+ 34%	A- 6%
B+ 9%	B- 2%
AB+ 3%	AB- 1%

How Much Blood Does a Person Have?
Adult males have about 12 pints of blood in their circulation and adult females have about 9 pints. (*Not sure how much a pint is? Use this link to convert the measurement into several dozen standards throughout the world) The donor's body replenishes the fluid lost from donation in about 24 hours. The Red Blood Cells that are lost are generally replaced in a few weeks. Whole Blood can be donated once every eight weeks.
 

Blood Donation Procedures (For "official" uses!)
Prospective donors must first successfully pass through several qualifying steps before proceeding with  the actual whole blood donation process, which takes about 20 minutes. (Education-the potential donor is given information to read and familiarize themselves with the procedure and process; Health History-In which the potential donor gives specific health information and facts which are used to screen unsuitable donors; and Physical Exam-This includes the recording of vital stats like blood pressure, pulse, and temperature, as well as a few drops of blood being taken to test for anemia. If the potential donor fails any of the steps, or decides to discontinue at any time, they are permitted to leave.) For all those who pass now begin the actual donation process. First, the donor sits in a reclining chair. The skin covering the inner part of the elbow joint is cleansed. A new, sterile needle connected to plastic tubing and a blood bag is inserted into an arm vein. The donor is asked to repeatedly squeeze his or her hand to help blood flow from the vein into the blood bag. Typically, one unit of blood, roughly equivalent to a pint, is collected. After the blood is collected, it is sent to the laboratory for testing and component preparation. The donor is escorted to an observation area for light refreshments (such as Orange Juice and Cookies) and a brief rest period.
 

Blood Storage & Breakdown
Each unit of whole blood is normally separated into several main 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.)
• Platelets are stored at room temperature and may be kept for a maximum of five days.
• (Platelets are important in the control of bleeding and are generally used in patients with leukemia and other forms of cancer.)
• Fresh Frozen Plasma is usually kept in the frozen state for up to one year.
• (Fresh Frozen Plasma is used to control bleeding due to low levels of some clotting factors)
• Other products manufactured from blood include albumin, immune globulin, specific immune globulins and clotting factor concentrates. These blood products are commonly made by commercial manufacturers.

Whole Blood and Blood Components
Blood may be transfused as Whole Blood or as one of its components. Because patients seldom require all of the components of Whole Blood, it makes sense to transfuse only that portion needed by the patient for a specific condition or disease. This treatment, allows several patients to benefit from one unit of donated Whole Blood. Blood components include Red Blood Cells, Plasma, Platelets and Cryoprecipitated Antihemophilic Factor (AHF). Up to four components may be derived from one unit of blood. Improvements in cell preservative solutions over the last 15 years have increased the shelf-life of Red Blood Cells from 21 to 42 days.

Whole Blood is a living tissue that circulates through the heart, arteries, veins and capillaries carrying nourishment, electrolytes, hormones, vitamins, antibodies, heat and oxygen to the body's tissues. Whole Blood contains Red Blood Cells, White Blood Cells and Platelets suspended in a pertinacious fluid called Plasma.

If blood is treated to prevent clotting and permitted to stand in a container, the Red Blood Cells, weighing the most, will settle to the bottom; the Plasma will stay on top; and the White Blood Cells and Platelets will remain suspended between the Plasma and the Red Blood Cells. A centrifuge may be used to hasten this separation process. The platelet-rich plasma is then removed and placed into a sterile bag, and it can be used to prepare Platelets and Plasma or Cryoprecipitated AHF. To make Platelets, the platelet-rich plasma is centrifuged, causing the Platelets to settle at the bottom of the bag. Plasma and Platelets are then separated and made available for transfusion. The Plasma may also be pooled with Plasma from other donors and further processed, or fractionated, to provide purified Plasma proteins such as albumin, immunoglobulin and clotting factors.
 

Red Blood Cells are perhaps the most recognizable component of Whole Blood. Red Blood Cells contain hemoglobin, a complex iron-containing protein that carries oxygen throughout the body and gives blood its red color. The percentage of blood volume composed of Red Blood Cells is called the hematocrit; The average hematocrit in an adult male is 47 percent. There are about one billion Red  Blood Cells in two to three drops of blood, and, for every 600 Red Blood Cells, there are about 40 Platelets and one white cell. Manufactured in the bone marrow, Red Blood Cells are continuously being produced and broken down. They live for approximately 120 days in the circulatory system and are eventually removed by the spleen.

Red Blood Cells are prepared from Whole Blood by removing the Plasma, or the liquid portion of the blood, and can raise the patient's hematocrit and hemoglobin levels while minimizing an increase in blood volume. Patients who benefit most from transfusions of Red Blood Cells include those with chronic anemia resulting from disorders such as kidney failure, malignancies, or gastrointestinal bleeding and those with acute blood loss resulting from trauma or surgery. Since Red Blood Cells have reduced amounts of Plasma, they are well-suited for treating anemia patients who would not tolerate the increased volume provided by whole blood, such as patients with congestive heart failure or those who are elderly or debilitated. Red Blood Cells may be treated and frozen for extended storage (up to 10 years).
 

Plasma is the liquid portion of the blood, a protein-salt solution in which red and White Blood Cells and Platelets are suspended. Plasma, which is 90 percent water, constitutes about 55 percent of blood volume. Plasma contains albumin (the chief protein constituent), fibrinogen (responsible, in part, for the clotting of blood), globulins (including antibodies) and other clotting proteins. Plasma serves a variety of functions, from maintaining a satisfactory blood pressure and volume to supplying critical proteins for blood clotting and immunity. It also serves as the medium of exchange for vital minerals such as sodium and potassium, thus helping maintain a proper balance in the body, which is critical to cell function. Plasma is obtained by separating the liquid portion of blood from the cells.

Fresh Frozen Plasma is frozen within hours after donation to preserve clotting factors, stored for one to seven years, and thawed before it is transfused. It is most often used to treat certain bleeding disorders when a clotting factor or multiple factors are deficient and no factor-specific concentrate is available. It can also be used for Plasma replacement via a process called plasma exchange.

Cryoprecipitated AHF is the portion of Plasma that is rich in certain clotting factors, including Factor VIII, fibrinogen, von Willebrand factor and  Factor XIII. Cryoprecipitated AHF is removed from Plasma by freezing and then slowly thawing the Plasma. It is used to prevent or control bleeding in individuals with hemophilia and von Willebrand disease, which are common, inherited major coagulation abnormalities. Its use in these conditions is reserved for times when viral-inactivated concentrates containing Factor VIII and von Willebrand factor are unavailable and Plasma components must be used.
 

Platelets (or thrombocytes) are very small cellular components of blood that help the clotting process by sticking to the lining of blood vessels. Platelets are made in the bone marrow and survive in the circulatory system for an average of 9-10 days before being removed from the body by the spleen. The Platelet is vital to life, because it helps prevent both massive blood loss resulting from trauma and blood vessel leakage that would otherwise occur in the course of normal, day-to-day activity. Units of Platelets are prepared by using a centrifuge to separate the platelet-rich Plasma from the donated unit of Whole Blood. The Platelet-rich Plasma is then centrifuged again to concentrate the Platelets further.

Platelets may also be obtained from a donor by a process known as apheresis, or plateletpheresis. In this process, blood is drawn from the donor into an apheresis instrument, which, using centrifugation, separates the blood into its components, retains the Platelets, and returns the remainder of the blood to the donor. The resulting component contains about six times as many Platelets as a unit of Platelets obtained from Whole Blood. Platelets are used to treat a condition called thrombocytopenia, in which there is a shortage of Platelets, and in patients with abnormal Platelet function. Platelets are stored at room temperature for up to five days.
 

White Blood Cells are responsible for protecting the body from invasion by foreign substances such as bacteria, fungi and viruses. The majority of White Blood Cells are produced in the bone marrow, where they outnumber Red Blood Cells by two to one. However, in the blood stream, there are about 600 Red Blood Cells for every White Blood Cell. There are several types of White Blood Cells. Granulocytes and macrophages protect against infection by surrounding and destroying invading bacteria and viruses, and lymphocytes aid in the immune defense.

Granulocytes can be collected by apheresis or by centrifugation of Whole Blood. They are transfused within 24 hours after collection and are used for infections that are unresponsive to antibiotic therapy. The effectiveness of White Blood Cell transfusion is still being investigated.