Blood types: A, B, AB, O (and compatible groups)


Blood types are usually classified according to the presence or absence of agglutinins, which are also called antibodies or proteins in the blood plasma. Therefore, blood can be classified into 4 types according to the ABO system.

Blood Types
  • Blood A: This is most common blood type and it contains antibodies which are against the blood type B. It is also called anti B and it can only receive blood from people with type A or O.
  • Blood B: This is one of the rarest types and it contains antibodies which are against type A, also known as anti-A. It can only receive blood from people with blood type B or O.
  • Blood AB: This is also one of the rarest types and it has antibodies against A or B. This means people with this blood type can receive blood from people with all types without having any reaction.
  • Blood O: This type is also known as the universal donor and it is one of the most common blood groups. It has anti-A and anti-B antibodies and it can only receive blood from people with blood type O. They may not receive from others as agglutination of red blood cells will take place.

People with the type O blood type can donate blood to anyone but they can only receive blood donations from people with the same blood type. On the other hand, people with type AB can receive blood from anyone but they can only donate to people with the same blood type. It is therefore important that the transfusion is only done among people with the right compatibility, otherwise the transfusion may be cause reactions which can lead to complications.

Depending on the the blood type, there are different types of diet that are suitable for consumption.

What is the Rh factor


Aside from classification of blood types according to the ABO system, blood types are also classified according to the RH factor which can either +ve or -ve. The Rh factor is characterized by an antigen that is present in the red blood cells and it should be taken into account during the transfusion process. This is because if not, it may result in serious complications related to blood transfusion.

Rh Blood Group System

People that have the Rh factor are classified as Rh+ and they can receive blood from people that have Rh+ and Rh-. However, they can only donate to those that have Rh+. On the other hand, people who do not have the Rh factor are classified to be Rh-. They can therefore donate blood to people who either have or do not have the Rh factor but can only receive from people who are Rh-.

Compatibility table for blood donation

The following table shows who can donate blood and who can recieve blood and from whom:

 You can donate to:You can receive blood from:
Blood type A+AB+ and A+A+, A-, O+ and O-
A- type bloodA+, A-, AB+ and AB-A- and O-
Blood type B+B+ and AB+B+, B-, O+ and O-
Blood type B-B+, B-, AB+ and AB-B- and O-
Blood type AB+AB+A+, B+, O+, AB+, A-, B-, O- and AB- (all)
Blood type AB-AB+ and AB-A-, B-, O- and AB-
O+ type bloodA+, B+, O+ and AB+O+ and O-
O-type bloodA+, B+, O+, AB+, A-, B-, O- and AB- (all)O-

What kind of blood type is your child?

Usually the blood type of a child is identified immediately after birth using the foot test. However, the blood type of the child can also be identified using routine blood tests. It can also be done upon the request of the child’s paediatrician so as to determine the diagnosis of a particular disease.

However, if the blood types of the parents are known, it is possible to identify the blood group of the child.

new born baby

During pregnancy, when the mother is Rh- and the baby is Rh+, there is a possibility that the pregnant woman will produce antibodies against the baby which may result to an abortion. Therefore, a pregnant woman with this type of blood should consult a gynaecologist who will administer anti-D immuniglobin injection. Nevertheless, there are never any serious problems during the early periods of pregnancy.

Who can donate blood?

Blood donation takes about 30 minutes to be done and there are some requirements that must be met before the blood is donated:

  • Be between 18 and 65 years old, however people aged 16 years old can donate blood as long as they have permission from their parents or guardians and they meet the other requirements for donation
  • Weigh more than 50 kg
  • If you have had a tattoo, wait up to 6 to 12 months to make sure that you have not been infected with any type of hepatitis and that you remained healthy throughout the period
  • Never used injectable illicit drugs
  • Wait at least for one year after healing some STD

Men can only donate blood once every 3 months and not more than 4 times a year. Women can donate every 4 moths and for a maximum of 3 times a year. This is because women lose blood every month through menstruation and they therefore take long to replenish the amount of blood lost.

Before donating blood, it is important to avoid consumption of fatty foods at least 4 hours before the time of donation, and one should also avoid fasting. It is therefore recommended to take a light meal before donating blood and after donation, one should take a snack that in most cases, is provided at the centre for donation. It is also advisable to drink plenty of fluids, not to smoke at least 2 hours after donation and not perform very intense physical activities as these may increase the risks of fainting.

How to donate blood

When someone wants to donate blood, they should go to one of the blood donation centres and fill out a form that contains various questions about their health and lifestyle habits. This form will be analysed by a health specialist and if it is approved then then can comfortably sit on a chair ready for the donation.

It begins by a nurse putting a needle in the vein of the arm, through which the blood will flow into a bag of its own for storage of the blood. The donation usually lasts approximately half an hour. It is therefore possible to spare sometime off work and go for the donation without having any implications on your salary.

At the end of the donation, the donor is usually offered a snack so that they may recharge. This is because the donor may feel weak and experience dizziness. However, the amount of blood removed from the body does not usually reach half a litre if the total blood and therefore the body will soon replace the loss.

It is safe to donate blood without the donor having any risk of contracting any disease. This is because the donation process follows the national and international blood safety standards of the Ministry of Health, the American Association an the European Council of Blood Banks.

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Cornelius Arthur
I am an English language and literature teacher. I have worked in many cities of the world. I am currently producing content at upwork as a freelance. I find and produce the right content by doing good research.


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