Editor's note:

  June 14th is the 17th World Blood Donor Day. This year's theme is "Safe Blood Saves Life" and the slogan is "Donate Blood to Make the World Healthier". During the epidemic, young students, cadres, and the masses conveyed love and combated the epidemic with actual actions. They donated blood for free to fight the epidemic and tried their best to help more people in need.

 Will blood donation affect your health?

  The total amount of blood in a normal person accounts for about 7-8% of the body weight. The total amount of blood in an adult is 4000-5000 ml. A blood donation of 200-400 ml only accounts for 5-10% of the total blood volume. The general blood loss is less than 600 ml. No blood transfusion is required.

  20-25% of the blood in the human body is stored in "storage reservoirs" such as the spleen, liver, lungs, skin, etc. The spleen is the largest "reservoir reservoir" in the human body and can store 20% of the total amount of human blood. When blood is needed for human blood circulation, "storage banks" such as the spleen will continuously release blood into blood vessels to participate in blood circulation. The human bone marrow has a powerful compensatory function. Under certain conditions, the hematopoietic function can be increased to 6-8 times normal.

  Generally, the plasma and inorganic salts lost by the human body after blood donation can be replenished by interstitial fluid infiltrating into the blood vessel within 1 to 2 hours; plasma protein can also be recovered within one day. However, the recovery of red blood cells and hemoglobin is slow, and it usually takes 3 to 4 weeks.

  Therefore, healthy people donate blood will not affect health, donate 5% of you, other people may get a chance of life.

Is transfusion therapy safe?

  Blood transfusion refers to a treatment method in which the blood of a healthy person is infused into a patient through veins, and is widely used in clinic. Blood transfusion therapy is performed between individuals with the same blood type as much as possible. Before blood transfusion treatment, the blood has generally passed the basic infectious disease test and proved safe before it can be used.

  However, there is no absolutely safe blood, and any form of blood transfusion therapy may produce infections and complications. There are also blood donors who are in the window of infection and cannot be detected with existing methods. Therefore, blood transfusion is relatively safe, but there are risks, and the indications should be strictly controlled.

  If blood transfusion is really necessary, the blood of the patient should be considered first, and the corresponding component blood transfusion should be carried out.

  General blood products include fresh whole blood, red blood cells and platelets. Blood transfusion can improve the utilization rate of blood. One blood is multi-purpose and saves blood.

  Constituent blood is separated by red blood cells, platelets, plasma and other component blood by a blood cell separator, and the remaining components are returned to the donor.

  Fresh blood generally refers to anticoagulated blood within a few hours after blood collection. There is little change in tangible and non-forming components in the blood. It is mainly used for acute massive blood loss. It provides both red blood cells and plasma.

  For platelet supplementation, no more than 24 hours; for supplementation of blood coagulation factors, especially factor VIII and factor V, it must not exceed 24 hours.

  For anemia, if you want to increase hemoglobin, you can use component transfusion and infusion of red blood cell suspension.

 Is bone marrow donation a bone marrow extraction?

  It turned out that bone marrow donation is really to extract bone marrow in the iliac bone and other parts, the extraction process needs to be performed in the operating room, and there are many puncture points on the donor, which is still very painful.

  At present, many transplant centers use hematopoietic stem cells for transplantation, that is, hematopoietic stem cells are directly collected from peripheral blood. The process is similar to that of ordinary blood donation, but a large number of hematopoietic stem cells in the bone marrow need to be mobilized into peripheral blood. The pain of the donor is greatly reduced and there is no need to go to the operating room.

  What are the donated things? Generally, it is 50 to 100 milliliters, which is less than the amount of whole blood donated at one time; it contains part of the blood components, and the collected material is about 10 grams of hematopoietic stem cells.

  Will donating hematopoietic stem cells affect health? There is currently no evidence that donating hematopoietic stem cells can affect health; we all know that hematopoietic stem cells have a strong ability to regenerate. Under normal circumstances, various cells of the human body are constantly being metabolized every day, undergoing a cycle of generating aging and death.

  After blood loss or donation of hematopoietic stem cells, the bone marrow can be stimulated to accelerate hematopoiesis. Within 1-2 weeks, various blood cells in the blood can return to their original levels.

  Expert: Jing Hongmei (Chief physician of the Department of Hematology, Peking University Third Hospital, doctoral supervisor, member of the Standing Committee of the First Committee of the Hematology Branch of the Chinese Geriatrics Society, member of the Standing Committee of Lymphoma of the Chinese Geriatric Health Association, specialist in hematology of the Beijing Medical Association (Executive director of the branch, member of the eighth editorial committee of the Chinese Journal of Experimental Hematology)

  Acknowledgement: China Science and Technology Association: Guangming reporter Zhan Zhao