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FAQs - about blood

If you have a question on blood and how it's used please take a look at the FAQs below.

You can also check the full list of FAQs for comprehensive information on blood donation.

  1. 01

    Everybody has a particular blood type which is jointly inherited from their mother and their father. There are two major blood type systems – the ABO system and the Rhesus system (Rh factor) - the different combinations of which result in eight major blood types.

    When a transfusion is required, it is preferable that patients receive blood of the same ABO and Rh(D) type. However, in an emergency, if the required blood type is unavailable, a patient may be given blood of a different, but compatible type.

  2. 02

    Red cells give blood its colour and account for 40-50% of its volume.  

    • Their main function is to carry oxygen from the lungs to all the cells of the body and remove waste products such as carbon dioxide.
    • Transfusions are used to treat people with severe anaemia, those whose red blood cells do not function adequately and people experiencing severe bleeding such as accident victims and patients undergoing surgery.
    • Red cells are stored in a refrigerator and have a shelf life of up to 42 days.

    Platelets are components of blood that assist in the blood clotting process.

    • They are literally tiny plates that wedge together covering tears in the blood vessels and preventing blood from leaking into surrounding tissue.
    • The primary use of platelets is in the treatment of people with various cancers and other diseases such as leukaemia where the bone marrow is unable to produce adequate numbers of platelets, as well as for people receiving medical treatments like chemotherapy which can decrease a person's platelet count. Platelets are also used to treat people suffering severe blood loss.
    • Platelets are stored at room temperature and have a shelf life of only 5 days. This is why it is vital to have a constant flow of blood donations coming in.

    Plasma is the straw coloured fluid in which the red cells, white cells and platelets are suspended.

    • Plasma is the most versatile component of blood as it can be processed into a variety of products and each product can be used to treat a number of potentially life-threatening conditions.
    • Plasma is stored frozen and has a shelf life of up to 12 months

    It is possible to give platelet or plasma-only donations every 2 weeks - find out more.

  3. 03

    A single unit of blood taken during a whole blood donation is about 470mL (less than half a litre), which is less than 10% of your total blood volume. Your body keeps on replenishing blood all the time whether you give blood or not, so this amount is quickly replaced.

  4. 04

    An average size adult has a blood volume of around 4.5 - 5.5 litres.

  5. 05

    Whole blood donations are separated into their components (red cells, platelets and plasma). After processing, red cells are refrigerated and can be stored for up to 42 days. Platelets are stored at room temperature and can be stored for up to 5 days. Plasma is frozen and can be stored for up to 12 months.

    Whilst a significant proportion of the plasma is used for direct transfusion to patients, the majority of donated plasma is further processed into a number of very important plasma products. These plasma products include immunisations against chicken pox, hepatitis B and tetanus; clotting factors for the treatment of patients with haemophilia; protein products for the treatment of patients with burns, liver and kidney diseases; and immunoglobulin products for the treatment of patients with antibody deficiencies and other disorders of the immune system.

  6. 06

    All blood donations are tested and processed and available for use between 24 and 48 hours after collection. Whole blood is separated into its components (red cells, platelets, plasma). After processing, red cells can be stored for up to 42 days; plasma is frozen and can be stored for up to 12 months; and platelets have a shelf-life of only five days.

  7. 07

    After donation, all blood is tested at every donation for blood type, the presence of red cell antibodies and for the following infections: HIV1 & 2, hepatitis B & C, HTLV I & II and syphilis. Some donations are also tested for malaria depending on the donor's answers to the questions on the donor questionnaire.

    Find out more about testing.

  8. 08

    Distribution of the blood and blood products to hospitals is determined by when, where and how much blood will be needed at any given time. In emergencies, blood can be transported between hospitals, towns and states/territories so that we can ensure that the blood is available when it is needed.