What are the most common blood disorders

With the first part of this two-part series about blood, we focussed on the different blood types and blood donation in South Africa. In this part we share some interesting facts about blood and take a closer look at some of the most common blood diseases. Blood disorders are important to be aware of as, if something is wrong with your blood, your overall health can be affected in a major way. In most cases, diseases of the blood occur when one or more types of blood cells become impaired or malformed, leading to an inability to function as well as they should. Here we take a look at some of the most common blood disorders according to the type of cells they affect.

Red blood cells contain haemoglobin to which oxygen attaches itself and is then carried around to the various tissues within the body.


Anaemia is caused by a lack of mineral iron in the blood. Iron is needed to help the body produce the protein haemoglobin, which is responsible for transporting life-giving oxygen from the lungs to all the body’s tissues. Without its production, organs would not receive oxygen and would begin to die.

Sickle cell anaemia (SCA)

This is a form of anaemia in which the usual disc-shaped red blood cells become sickle-shaped. As a result, the amount of oxygen that is able to be carried to the body’s tissues becomes limited. The unusual shape can also lead to the cells becoming stuck in the vessels, causing blockages which can lead to organs not receiving the oxygen they need to function. SCA is an inherited disorder that can only be passed down to a child if both the parents have the condition.

White blood cells are responsible for fighting infection in the body.


Lymphoma is a type of blood cancer that develops in the lymph system when white blood cells become malignant, then multiply and spread. There are two main types of lymphoma, namely Hodgkin’s and non-Hodgkin’s. Typically, chemotherapy and/or radiation are required to combat the disease.


Also a kind of blood cancer, leukaemia is similar to lymphoma except that the malignancy and multiplication takes place within the bone marrow (the flexible tissue located on the inside of the bones). The most effective treatment option is often a bone marrow transplant.

Without blood platelets, blood would not be able to clot, which could to lead to death should a severe injury occur.

Idiopathic thrombocytopenic purpura

This is a condition with an unknown cause that results in a persistently decreasing number of platelets being produced. There are usually very few symptoms that present, although small red spots on the skin, abnormal bleeding and bruising can take place.

Primary thrombocythemia

Also with an unknown cause, this condition is caused when the body over-produces platelets that also do not work properly, resulting in the sufferer experiencing excessive clotting or bleeding (or both).

This is the pale yellow liquid part of the blood in which the other blood cells are suspended. It makes up 55% of the blood and is about 92% water.


Typically caused through the infection of a wound, sepsis is when the bacteria moves into the blood causing widespread infection. This can lead to fever, respiratory failure and low blood pressure. If untreated, sepsis can be fatal.


A genetic condition, haemophilia is when there is a deficiency of the proteins responsible for helping the blood to clot. There are many forms of this condition, ranging from mild to life-threatening. 

To end off this informative two-part series on blood, here are some interesting facts about the red, life-giving liquid:

  • New-born babies have approximately one cup of blood in their bodies.
  • It takes one blood cell roughly 30 seconds to complete one circuit around the body.
  • The heart will pump nearly 1.5 million barrels of blood during a person’s lifetime – this is enough to fill approximately 200 train tank cars.
  • By week 20 of pregnancy, women will have 50% more blood in their system than before conception.
  • Gold can be found in the blood – about 0.2 milligrams.
  • Approximately 8% of a person’s body weight is blood.
  • In an emergency, coconut water can be used as a substitute for blood plasma.
  • The strange, bright dots you see floating around when you look up at the sky are actually white blood cells.
  • It would take 1,200,000 mosquitoes, each sucking once, to completely drain the average human of blood. It’s also only female mosquitoes who drink human blood and they prefer blood type O over all other types of blood. 
  • Red blood cells only live for 120 days.
  • The human cornea has no blood supply and extracts oxygen directly from the air. 
  • Oxygen-rich blood is bright red in colour, whereas oxygen-low blood is dark red. 

Blood, together with the heart and lungs, forms an important part of the circularity system and without it, there would be no way of transporting vital, life-giving oxygen around the body to the various tissues and organs.

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