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This application is a service of the Singapore Government.

Health Sciences Authority

Blood Components and Their Uses


Blood Components

Blood delivers oxygen and nutrients to the cells and transports waste substances away from them. In every two to three drops of blood, there are about one billion red cells. And for every 600 red blood cells, there are about 40 platelets and one white blood cell. Currently, there is no viable substitute for human blood.

In today’s medical treatment, patients may be given whole blood or specific blood components required for their condition. These components include:

Red Cells

Each red blood cell has haemoglobin that carries oxygen to the cells of the body and transports carbon dioxide from the cells to the lungs for excretion. Manufactured in the bone marrow, red blood cells are continuously being produced and broken down. They live for approximately 120 days in the circulatory system before they are removed by the spleen.


White Cells

White cells are responsible for cleansing the body and fighting off infections. However, they are usually not used for transfusion as the white cells from donations are not useful after 24 hours.


These are small cell fragments in your blood whose main function, along with clotting factors, is to stop bleeding. When a blood vessel is damaged, platelets will become “glued” together at the damage site to form a platelet plug, which prevents blood from leaking out.


Approximately 55% of blood is plasma. Plasma is like a river that carries the solid cells and platelets to all parts of the body. They contain special proteins such as albumin and immuno-globulins which are antibodies that fight infection and cancer, as well as clotting factors – special proteins that help blood to clot.
To find out more about lipemic plasma, click here.

Common Uses of Blood and Its Components

Blood /
Blood Components
Red blood cells Replacement of red blood cells in patients with anaemia or bleeding secondary to trauma, surgery or childbirth.
Platelets Replacement of platelets in bleeding patients or patients going for procedures. Platelet counts may be low due to medical conditions such as blood malignancies, cancer patients on chemotherapy or dengue. 
Fresh frozen plasma Replacement of clotting factors in bleeding patients or patients going for procedures. Clotting factors may be depleted in bleeding or infection.

Relationship between Haemoglobin and Iron

Iron is one of the important elements in the production of haemoglobin, which is responsible for carrying oxygen to your body tissues. When there is enough iron to meet your daily needs, any additional iron is stored in your body for future use.

Iron Depletion

Iron depletion happens when the iron stores are consumed to meet your body's needs faster than they are being replenished. If the shortage of iron is not remedied, you will eventually develop iron-deficiency anaemia.

Iron-Deficiency Anaemia

In iron-deficiency anaemia, important organs such as the heart and brain receive insufficient oxygen and you may experience palpitations, angina (chest pains), headaches, dizzy spells, tiredness or breathlessness. You can find out more about iron-deficiency anaemia and how you can prevent it here

How Much Iron Do I Need?

If you are a regular blood donor who makes a contribution every 12 weeks, you will need approximately a total of 3-4 mg of iron each day. While the average daily requirement for males or females is 1 mg or 1.5 mg respectively.

As only 5% to 10% of the iron that is present in your diet is actually absorbed by your body, your daily diet should give you a total of 45 mg of iron if you are male, and 50 mg of iron if you are female.

Therefore, your iron requirement is as follows:


  Male Female
Daily iron requirement 1 mg 1.5 mg
Amount of iron needed in daily diet 15 mg 15 mg

Regular Donor

  Male Female
Daily iron requirement 3 mg 3.5 mg
Amount of iron needed in daily diet 45 mg 50 mg

Making a Donation

If you would like to make a donation, please refer to the table below as a guide. Our staff may also advise you on the type of donation which you could make that will help patients the most. These changes from time to time depending on the patients’ need.


Attention all AB Blood Donors. We need your platelets and plasma!

Do you know your blood type makes you an ideal candidate for donating platelets or plasma?

Group AB platelets and plasma can be given to any recipient regardless of their ABO blood type. Thus they are called universal platelet or plasma donors.

Type AB platelets are often given to neonates and infants during emergency platelets transfusions. Exchange transfusions for new born baby with severe jaundice also require AB plasma combined with group O red cells in most cases.

If you are a group AB regular whole blood donor and weigh at least 50kg, please consider switching to apheresis donation of platelets or plasma.


Blood Group Preferred Type of Donation
1st Choice 2nd Choice 3rd Choice
A+ Whole Blood Plateletpheresis Plasmapheresis
B+ Plateletpheresis Whole Blood Plasmapheresis
O+ Whole Blood Plateletpheresis -
AB+ Plasmapheresis Plateletpheresis Whole Blood
A- Double-units Red Cell Apheresis Whole Blood -
B- Whole Blood Plateletpheresis -
O- Double-units Red Cell Apheresis Whole Blood -
AB- Plasmapheresis Plateletpheresis Whole Blood

Please click here to find out more on the blood donation process.