10 facts on Blood

Source: WHO

Blood transfusion saves lives and improves health, but millions of patients requiring transfusion do not have timely access to safe blood. Every country needs to ensure that blood supplies are sufficient and free from HIV, hepatitis viruses and other chronic infections that can be transmitted through unsafe transfusion.

In high-income countries, transfusion is most commonly used to support invasive medical procedures and surgeries like open-heart surgery and organ transplant. In low- and middle-income countries it is used more often in pregnancy-related complications and severe childhood anaemia. As the demand for blood is increasing, blood shortages are common. More blood donors are needed to replace those that are lost every year due to ill health, retirement and relocation.

It is estimated that around 93 million blood donations are given every year. About 50% of these are donated in low- and middle-income countries where nearly 85% of the world’s population lives. The average blood donation rate is more than 13 times greater in high-income countries than in low- and middle-income.

Blood is collected in about 8000 blood centres spread all over the world. The average annual blood donation per centre varies from 30 000 in high-income countries to 7500 in middle-income countries and around 3700 in low-income countries.

Voluntary unpaid donors account for 100% of blood supplies in 58 countries. Since the inception of World Blood Donor Day in 2004, 111 countries have reported an increase in the number of voluntary donations. But in 45 countries, less than 25% of blood supplies come from voluntary unpaid donors.

The average donation rate in high-income countries is 45.4 donations per 1000 people. This compares with 10.1 donations per 1000 people in middle-income countries and 3.6 donations in low-income countries. If 1% to 3% of a country's population donated blood, it would be sufficient to meet the country's needs. But in 77 countries, donation rates are still less than 1%.

Adequate stocks of safe blood can only be assured through regular donation by voluntary unpaid blood donors, because the prevalence of bloodborne infections is lowest among these donors. It is higher among donors who give blood only as a replacement when it is required for a family and among those who give blood for money or other forms of payment.

Donated blood should always be screened for HIV, hepatitis B, hepatitis C and syphilis prior to transfusion, but in 42 countries (out of 173 countries reporting in 2008) not all donated blood is tested for one or more of these infections. Testing is not reliable in many countries because of staff shortages, poor quality test kits, irregular supplies, or lack of basic laboratory services.

Separating blood into its various components allows a single unit of blood to benefit several patients and provides a patient only the portion of blood which is needed. About 97% of the blood collected in high-income countries, 63% in middle-income countries and 28% in low-income countries is separated into blood components.

Often transfusions are prescribed when simpler, less expensive treatments might be equally effective. This exposes some patients to the needless risk of infections or severe transfusion reactions due to incompatibility of blood groups. Safe clinical transfusion practices are fundamental for transfusion to be truly life-saving with minimal risk.