How much blood can you donate? before going into details, let’s do a bit of clarity. Blood is a circulating liquid that represents 7-8% of our body weight. It consists of about 55-60% of a liquid part, the plasma, that is, water in which many substances are dissolved (sugars, fats, proteins, coagulation factors, antibodies, hormones, vitamins, etc..), and for the rest of cells: Red Globules, White Globules and Platelets. The Red Globules, also called Emazie or Erythrocytes, are the most numerous cells (about 4-5 million per cubic millimetre) .
Are rich in a red pigment containing iron, hemoglobin, which transports oxygen to all cells of the body and exchanges it with carbon dioxide through respiration, on their surface there are special substances that differentiate individuals according to blood groups ABO, Rh, etc.. The White Globules, also called Leukocytes, are divided into granulocytes (neutrophils, basophils, eosinophils), monocytes and lymphocytes, and intervene in different ways in the defense of our body from external aggression (viruses, bacteria, fungi, tumors, etc..). Platelets intervene in the treatment of bleeding and, in collaboration with plasma factors, in the mechanisms of coagulation.
What is the purpose of donate blood?
Blood used for transfusion is of exclusive human origin. It is a limited and perishable therapeutic resource and, in order to avoid deficiencies, blood should only be used when there is a precise clinical indication. Virtually all of the whole blood collected through donations is fractionated into its blood components in the blood transfusion services of the region; a large part of the plasma is then sent for industrial processing to obtain blood-derived products. Among the blood components.
The Red Cell Concentrates are used to correct serious anaemia of various kinds (in leukaemia, in tumors, after bleeding, in thalassemia, etc..), the Platelet Concentrates are used to buffer or prevent severe bleeding resulting from defects in the number or function of these cells, the fresh Plasma for clinical use is used to buffer or prevent certain bleeding resulting from defects in coagulation. Among the hemoderivatives, albumin is useful to correct the widespread edema resulting from severe liver failure, immunoglobulins are used to combat serious infections, coagulation factors are essential for the treatment of bleeding that accompanies their deficiency or congenital absence, as in hemophilias.
How much do you have to weigh to donate blood
In general, the donor must be a healthy person, with a body weight of not less than 50 kg and an age between:
– 18 – 65 years (as per new decree, after critical assessment of the main age-related risk factors, donation can be allowed up to 70 years) for whole blood donation (in case of first donation must not exceed 60 years);
– 18 – 60 years for apheresis donation.
Before being included in the blood donation program, the candidate donor who meets the above requirements, is subjected to a selection procedure that, through the performance of clinical, instrumental and laboratory tests, defines its suitability, to safeguard its safety and that of the patients who will receive the transfusion.
Who can’t give blood
Infectious diseases (viruses, bacteria, fungi) can be transmitted through the blood, so it is important to exclude temporary or permanent donations:
– Anyone who has contracted a type B or C viral hepatitis or an infection with the HIV/AIDS virus, even in the past, should be excluded from donation;
– Those who use drugs, or excessive use of alcoholic beverages (chronic alcoholism);
– Those who have undergone major surgery or endoscopic examinations (e.g. gastroscopy) or blood transfusion for less than a year, or have had a birth or an interruption of pregnancy;
– Those who have been returning from a malarial endemic zone for less than six months;
– Those who engage in sexual conduct at high risk of transmission of infectious diseases, including those who have sex, even if protected, with unknown persons who may be affected by viral hepatitis or HIV infection or have been addicted. In addition, certain clinical conditions make the donor unfit for blood donation in order to protect his own health:
– People who have suffered or are suffering from seizures and epilepsy;
– People who have suffered or are suffering from cardiovascular, respiratory or major gastrointestinal diseases, chronic kidney disease, blood disorders, neoplasms or malignant diseases;
– Who has had an organ transplant.
How much blood can you donate
450 millilitres of blood are taken: the donor’s body is able to reconstitute the liquid portion of the blood within a few hours, while the corpusculated portion may take longer, but the complete reintegration still takes place within a few days. The Ministerial Decree 25/01/2001 establishes how much blood can be donated. The man can donate the blood for a maximum of four times in a year, while women of childbearing age can do it twice. A minimum of ninety days must elapse between donations. After taking the donor, it is not recommended to practice risky activities or hobbies for at least 24 hours and to take a good amount of liquids (such as water, milk, tea or fruit juices) to replenish those that have been donated.
What is apheresis?
Apheresis is a special technique of sampling with which it is possible to subtract one or more blood components, returning to the donor the blood components that are not intended to be collected. In particular, by returning the red blood cells, greater quantities of plasma or platelets can be taken away because the body recovers very quickly the losses of plasma, platelets, white blood cells. To perform apheresis, special equipment is needed, the cellular separators, to which the donor is connected in extracorporeal circulation. The circuit for extracorporeal circulation is sterile and disposable.
The donation of plasma in apheresis, plasmapheresis, lasts about 30 minutes, during which 550-650 millilitres of plasma are collected; the donor must have all the requirements for eligibility for whole blood collection but the hemoglobin can have even lower values (11.5 g /dl in women and 12.5 g /dl in men); up to 10 litres of plasma can be donated per year and the minimum interval between two plasmapheresis is 14 days (as well as between a plasma donation and a whole blood donation, while one month between whole blood and plasma).
The donation of platelets in apheresis, platelet-aferesis, has a duration of about 90 minutes and requires, in addition to the requirements for the donation of whole blood, a number of circulating platelets exceeding 150-200,000/mmc; the maximum number allowed is 6 platelet-aferesis per year. In addition to these donations, the Ministerial Decree 25/1/01 provides for the possibility and lays down the rules for the execution of multiple donations of blood components in apheresis, such as the donation of platelets and plasma or platelets and red blood cells or double platelets, or for the donation of stem cells.
Are there any risk to your health by donating blood
Possible undesired and, in any case, infrequent effects of blood donation procedures are: localised pain or formation of hematoma at the point of insertion of the needle, lowering of pressure, dizziness, sweating, sometimes fainting, nausea and vomiting. Involuntary muscle contractions or seizures can rarely occur (especially in people who have already suffered from similar seizures in the past and have not reported them to the physician). The medical and nursing staff is always available to deal promptly and remedy any inconvenience. However, there is no risk of infection with the donation, since the material used is totally sterile and disposable, both for whole blood and for all apheresis procedures.
Warning after the donation
Apart from the short rest period immediately after the donation and the light breakfast, the donor must not carry out any risky activities or hobbies (e.g. driving public transport, using stairs, working on scaffolding, climbing, diving,…) within 24 hours after the donation. On the day of the donation, it is advisable to introduce more liquids (e.g. water, fruit juice, tea or milk, etc.) to replenish the donated ones. In addition, if the donor has any doubts as to whether the blood he has donated should be used, he is encouraged to ask the medical staff present at the collection site to dispose of his donation in order to better protect the health of the transfused patients. Finally, always for the purposes of protecting the recipients, the donor must promptly inform the staff of the blood bank of any illnesses that may have occurred in the days following the donation, with particular reference to infectious diseases.