By Yesha Shukla
Published 11:53 EST, Mon November 1st, 2021
Donating blood is common and a highly beneficial thing to do. Many selfless individuals donate their blood yearly which benefits sick patients all around the world. Each year, an estimated 6.8 million people in the United States alone donate blood, resulting in their collection of 13.6 million units of whole blood and red blood cells. However, many often question how exactly this donated blood is collected, processed, stored, and used which is exactly what this article aims to investigate.
Types of Blood Donations
The standard types of blood donation must be first understood before answering such a question because the type of blood being donated heavily influences the method in which it is collected. Beginning with a standard blood donation, this consists of plasma, red and white blood cells, platelets, antibodies, and other components. Plasma, also known as plasmapheresis, is another type of donation that separates plasma from the other components. This is done using a special machine and red blood cells are returned to the donor in cycles throughout the donation. Plasma is often given to individuals in emergency and trauma situations to help stop bleeding. Lastly, platelet donation–or plateletpheresis–is conducted in a similar way to plasma donations, but red cells and plasma are returned to the donor. These are typically given to individuals with clotting problems, cancer patients, or those who will have organ transplants or major surgeries. Additionally, a less common donation includes autologous which occurs before operation or transfusion where a person donates blood for their use. A directed or designated donation is also possible where a donor gives blood that is intended for a specific person to use.
How Much Blood Can Be Given?
It is crucial to understand exactly how much blood an individual can give before determining collection procedures as well. Healthy adults aged 18-75 are especially encouraged to donate as well as those with O negative blood because it can be given to anybody–of any blood type–if necessary. Regular donations collect around 470 mL of whole blood, which is 8% of an adult’s average blood volume. The body replaces this amount within 24 to 48 hours and replenishes red blood cells in 10 to 12 weeks. Additionally, individuals can donate whole blood every 12 weeks and plasma every 2 weeks.
How Is It Collected?
Now that the necessary basic information on blood collection is known, the specifics on how exactly it is collected can be investigated. First, pre-screenings are conducted to ensure the donor’s blood is healthy and will not damage a recipient. All donated blood is screened for blood-borne diseases–HIV, Hepatitis, Syphilis–and the donor must not suffer from a cold, flu, or any other illness at the time of donation. They must weigh at least 50kg and have a normal temperature and blood pressure. In the times of COVID, they must also be screened for the virus.
Taking blood is also a relatively simple process for regular blood donations. A blood pressure cuff or tourniquet is placed around the upper arm to fill a donor’s veins with more blood. A phlebotomist will then cleanse the area on the arm with an antiseptic and insert a sterile needle for the blood draw. This sterile needle is attached to a thin plastic tube and a blood bag. Once the needle is in, the donor should tighten their fists several times to help blood flow from the vein. Initially, blood is collected into tubes for testing and is then allowed to fill the blood bag. This process takes about 8 to 10 minutes and can be done sitting upright or laying down. When approximately a pint of blood is collected, the donation is complete and staff will remove the needle, elevate the donation arm, and apply slight pressure to promote clotting before bandaging the arm.
The process for platelet donations is however slightly different. Though the same pre-screening and sterile needle method still exist, a needle and plastic tube are connected to both arms. For such donations, an apheresis machine is used which collects a small amount of blood and separates the red cells, plasma, and platelets. It then returns the rest of the blood through the donor’s other arm and this cycle is repeated several times over about 2 hours.
How Is Blood Transported Post-Draw?
Directly after blood is taken, the donation, test tubers, and donor records are labeled with an identical bar code label. The donation is kept in ice before being taken to a processing center and the test tubes go to the lab. At the processing center, information about the donation is scanned onto a computer database before further steps are taken to prepare the blood to be shipped out to hospitals. Most whole blood donations are spun in centrifuges to separate them into transfusable components–red cells, platelets, plasma. Plasma may be processed into components–cryoprecipitate–which helps control the risk of bleeding by helping blood to clot. The red cells and platelets are leuko-reduced, meaning white blood cells are removed to reduce the participant’s possibility of reacting to transfusion. Each component is then packaged as a “unit” which is a standardized amount that doctors will use when transfusing a patient.
In parallel with all of this, the test tubes arrive at a testing laboratory where a dozen tests are performed to establish the blood type and test for infectious diseases. The test results from this are electronically transferred to a processing center within 24 hours and if results are positive, the donation is discarded.
When test results are received, units suitable for transfusion are labeled and stored. Specifically, red cells are stored in refrigerators at 6 degrees Celsius for up to 42 days, platelets are stored at room temperature for up to 5 days, and plasma and cryo are frozen and stored in freezers for up to 1 year. When blood is needed at hospitals, it is available for distribution 24/7. Hospitals typically keep blood units on their shelves, but some often call to receive units in times of urgency.
How Does Blood Transfusion Occur? What Products Are Made From Blood?
After the blood donation has reached the hospital, it is removed from storage and given to a patient in need through an intravenous line. This is a tiny tube that is inserted into a vein with a small needle and the transfusion process takes about 1 to 4 hours in total depending on the amount of blood needed.
Additionally, specific products can also be made from blood. From whole blood, red cells can boost the oxygen-carrying abilities of a patient’s blood. Platelets can clot blood assisting in those recovering from a severe hemorrhage. Lastly, plasma can be used in treating people with burns, cancer, and protecting people with brain and nerve diseases. Plasma contains antibodies and other important proteins used to make human immunoglobulin, human albumin, human coagulation factor IX, and many other specific products.
Blood donations travel a long way and though it only takes a couple of minutes to donate whole blood, a pint of blood could save a life in need. Due to the lack of donations during the pandemic, blood donations are at an all-time low; thus, individuals should donate blood if they can and are healthy enough to do so.
Yesha Shukla, Youth Medical Journal 2021
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