Abstract:- An adequate and reliable supply of safe blood can be assured by a stable base of regular, voluntary, unpaid blood donors. These donors are also the safest group of donors as the prevalence of blood borne infections is lowest among this group.  There is a marked difference in the level of access to blood between low- and high-income countries. The whole blood donation rate is an indicator for the general availability of blood in a country. Providing safe and adequate blood should be an integral part of every country’s national health care policy and infrastructure.The age profile of blood donors shows that, proportionally, more young people donate blood in low- and middle-income countries than in high-income countries. Demographic information of blood donors is important for formulating and monitoring recruitment strategies.The capacity to provide patients with the different blood components they require is still limited in low-income countries: 50% of the blood collected in low-income countries is separated into components, 59% in lower-middle-income countries, 92% in upper-middle-income countries, and 97% in high-income countries.In high-income countries, transfusion is most commonly used for supportive care in cardiovascular surgery, transplant surgery, massive trauma, and therapy for solid and haematological studies.Introduction:-Blood transfusion heals and improves health, but most of the patients do not find the right access to safe blood. Blood collected in an anticoagulant can be  transfused to a patient in an invariable state. This is known as blood transfusion. The age profile of blood donors show that, proportionally, more young people donate blood in low and middle income countries than in high income countries. Providing safe and sufficient blood should be an essential part of every country’s national health care policy and infrastructure. Blood transfusion is the crucial component of health care.WHO recommends that all blood donations should be tested  prior the use. Test of  HIV, hepatitis B, hepatitis C, and syphilis should be compulsory as they are the most frequently appearing diseases. Blood screening should be performed according to the quality system requirements.The risk of transmission of deadly diseases , including HIV and hepatitis, through unsafe blood and chronic blood shortages brought global  awareness,  the importance of safety and availability of blood. Aim:- To create an awareness of the safety and availability of blood and know the the advantages and disadvantages of blood donation.Objective:-  To study the safety and availability of blood Materials and Methods :-Various articles were referred based on the safety and availability of blood. These articles reveal the different types of blood donation, the safety measures taken during blood donation and blood transfusion. Usually there are three types of blood donors, they are Voluntary, Family/Friends and paid donors. Results and Discussion:-Blood transfusion is an indispensable component of health care. It contributes to saving millions of lives each year in both routine and emergency situations, permits increasingly complex medical and surgical interventions and dramatically improves the life expectancy and quality of life of patients with a variety of acute and chronic conditions.The articles state that ,there are three types of blood donors:-1. Voluntary ( unpaid) donors 2. Family/ replacement donors 3. Paid donorsVoluntary blood donors:- A voluntary non-remunerated blood donor gives blood, plasma or cellular components of his or her own free will and receives no payment, either in the form of cash or in kind which could be considered a substitute for money( 4)Family or replacement donors:- Family/replacement donors are those who give blood when it is required by a member of their own family or community(5). In most cases, the patient’s relatives are requested by hospital staff to donate blood, but in some cases it is compulsory for every patient who requires transfusion to provide a specified number of replacement donors on emergency admission to hospital or before planned surgery. Although donors are not paid by the blood transfusion service or hospital, there may be a hidden paid donation system in which money or other forms of payment are actually provided by patients’ families.(6)Paid or commercial donors:- Paid or commercial donors give blood in return for payment or other benefits that satisfy a basic need or can be sold, converted into cash or transferred to another person.(7)They often give blood regularly and may even have a contract with a blood bank to supply blood for an agreed fee. Alternatively, they may sell their blood to more than one blood bank or approach patients’ families and try to sell their services by posing as  family/replacement donors.(7)An adequate and reliable supply of safe blood can be assured by a stable base of regular, voluntary, unpaid blood donors. These are also the safest group of donors as the prevalence of blood borne infections is lowest among this group(8).Voluntary blood donors, particularly regular donors, are the first line of defence in preventing the transmission of HIV, hepatitis viruses and other blood-borne infections through the route of transfusion. Voluntary donors are recognised to be the safest donors because they are motivated by altruism and the desire to help others and by a sense of moral duty or social responsibility.(9)They have no reasons to withhold information about their lifestyles or medical conditions that may make them unsuitable to donate blood.Family/replacement donors are usually not informed about conditions that may make them unsuitable to donate blood. Even if there is a donor selection process to assess their eligibility to donate, they may be unaware of the significance of some of the questions in the donor interview.(10) In their eagerness to donate blood to save the life of a loved one or their fear of distressing or displeasing their family, replacement donors may conceal information about their health status or lifestyle behaviour.(10) This poses an increased risk of the transmission of infection, often resulting in a higher volume of donated blood that has to be destroyed because of evidence of infectious disease markers. Paid donors often lead lifestyles that expose them to the risk of HIV and other infections that could be transmitted through their blood. (11)The highest prevalence of transfusion-transmissible infections is generally found among paid or commercial donors.People who accept payment for their blood are primarily motivated by the prospect of money  gain rather than a desire to help save lives. The need to protect their income from blood “donation” compromises issues of honesty in the donor interview and they are highly unlikely to reveal reasons why they may be unsuitable to donate blood. (12)Further, they are often undernourished and in poor health and may give blood more frequently than is recommended, resulting in harmful effects on their own health.Blood transfusion:-A blood transfusion is the transfer of blood or blood products from one person (donor) into another person’s bloodstream (recipient). (13) This is usually done as a lifesaving process to replace blood cells or blood products lost through severe bleeding, during surgery when blood loss occurs or to increase the blood count in a  anemic patient. Blood can be provided from two sources: autologous blood (using your own blood) or donor blood (using someone else’s blood).The safest blood product is your own, so if a transfusion is likely, this is your lowest risk choice. Unfortunately this option is usually only practical when preparing for elective surgery. In most other instances the patient cannot donate their own blood due to the acute nature of the need for blood.(14)There are three types of blood transfusions. They are :1) Red Blood Cell TransfusionsA patient suffering from an iron deficiency or anemia, a condition where the body does not have enough red blood cells, may receive a Red Blood Cell Transfusion. This type of transfusion increases a patient’s hemoglobin and iron levels, while improving the amount of oxygen in the body.(15)2) Platelet TransfusionsPlatelets are a component of blood that stops the body from bleeding. Often patients suffering from leukemia, or other types of cancer, have lower platelet counts as a side effect of their chemotherapy treatments. Patients who have illnesses that prevent the body from making enough platelets have to get regular transfusions to stay healthy.(15)3) Plasma TransfusionsPlasma is the liquid part of the body’s blood. It contains important proteins and other substances crucial to one’s overall health. Plasma transfusions are used for patients with liver failure, severe infections, and serious burns.(15)Before a recipient receives a transfusion, compatibility testing between donor and recipient blood must be done. To assure a safe transfusion make sure your healthcare provider who starts the transfusion verifies your name and matches it to the blood that is going to be transfused. (16)Compatibility of ABO and Rh system-This chart shows possible matches in blood transfusion between donor and receiver using ABO and Rh system. The blood groups which were mentioned horizontally represent donors and the the blood groups which were mentioned vertically represent recipients.                                                                                Children are particularly vulnerable to shortages of blood in malarious areas because of their high requirement for transfusion arising from severe life-threatening anaemia resulting from malaria, often exacerbated by malnutrition.(16)Procedures followed before blood transfusion for safety:-Always the donor is first given a questionnaire detailing any history of diseases. Then their hemoglobin level is checked. Once this is done they take the sample of blood and send it for screening for possible infectious agents such as HIV and hepatitis. Now the blood of the patient is cross matched with patient’s blood sample to check it’s compatibility.The most important antigens in blood typing are the ABO and Rh antigens. Every individual has an ABO blood type (blood group A, B, AB, or O), which means their red blood cells may display antigen A, antigen B, both antigens, or neither antigen. Each person is also either positive or negative for the Rh antigen. Overall, these antigens can combine to give eight possible blood types. A complete blood count is performed to check levels of the various blood components including red blood cells, white blood cells, and platelets. Coagulation (clotting) tests are also done. During blood transfusion, vital signs such as temperature, heart rate, and blood pressure are carefully monitored. Some patients may get a sudden fever during or within 24 hours of the transfusion, which may be relieved with acetaminophen or paracetamol. This fever is a common reaction to the white blood cells present in donated blood.(17)(18)Conclusion:-Blood transfusion is the one of the crucial process where the diseases can be easily transmitted. The diseases which are transmitted are fatal and are chronic. Sometimes they may not be cured and may cause death. The precautions should be taken before blood transfusion or blood donation. The patients history of infectious diseases must be checked and the sample of blood must be collected and should be sent for screening.