The blood donation happens when a person voluntarily ready to transform their blood into communities without any charges, however, Donation may be of whole blood, or of specific components directly. Blood banks often participate in the collection process as well as the procedures that follow it.

The blood donation process discovered by English physician William Harvey in 1628 but after 36 years thy successfully done blood donation camp in England, the first blood transform done on a dog and Physician Richard Lower keeps dogs alive by transfusion of blood from other dogs people think it is funny incident but it is very seriously a successful transformation.

Today in the developed world, most blood donors are unpaid volunteers who donate blood for a community supply. In some countries, established supplies are limited and donors usually give blood, when family or friends need a transfusion. Many donors donate as an act of charity, but in countries that allow paid donation some people are paid, and in some cases there are incentives other than money such as paid time off from work. Donating is relatively safe, but some donors have to bruise where the needle is inserted or may feel faint. Potential donors are evaluated for anything that might make their blood unsafe to use. The screening includes testing for diseases that can be transmitted by a blood transfusion, including HIV and viral hepatitis. The donor must also answer questions about medical history and take a short physical examination to make sure the donation is not hazardous to his or her health. How often a donor can donate varies from days to months based on what component they donate and the laws of the country where the donation takes place. Ex. in many countries the doner have to wait for two to three weeks to rebuild their blood counts and proper growth of their blood portion. A typical donation is 450 milliliters of whole blood, though 500-milliliter donations are also common. Historically, blood donors in India would donate only 250 or 350 milliliters.

There are two main methods of obtaining blood from a donor. The most frequent is to simply take the blood from a vein as whole blood. This blood is typically separated into parts, usually red blood cells and plasma since most recipients need only a specific component for transfusions. The other method is to draw blood from the donor, separate it using a centrifuge or a filter, store the desired part, and return the rest to the donor. This process is called apheresis, and it is often done with a machine specifically designed for this purpose.

What precautions have to take donor after blood donation, they have to lay down for 10 to 15 minutes at the bead, then take light refreshments, such as orange juice and cookies, or a lunch allowance to recover speedy, The needle site wound is covered with a bandage and the donor is directed to keep the bandage on for several hours. And in last avoid strenuous exercise and games, alcohol and other kinds of physical exercise.

People from non-science backgrounds have questions that how doctors store blood for a long time?, here is the answer, Red blood cells, the most frequently used component, have a shelf life of 35–42 days at refrigerated temperatures. For long-term storage applications, this can be extended by freezing the blood with a mixture of glycerol, but this process is expensive and requires an extremely cold freezer for storage. Plasma can be stored frozen for an extended period of time and is typically given an expiration date of one year and maintaining supply is less of a problem.

Here is the table display that, which blood group person can donate to whom.