• Monday - Friday
    9am – 6pm
  • Saturday - Sunday
    10am – 2pm

How to Know Your Blood Type


The blood type is determined depending upon specific antigens present in your blood. You can know your blood type by asking the doctor at Private Blood Tests London to conduct a test, take at-home blood test or donate blood. The blood type includes two blood groups which are ABO and Rh.

Blood types are based on antigens on your red blood cells surface. An antigen is a kind of substance that produces immune response by the body against the substance.

Read on to know how to find out your blood type and what it means to you.

How you can determine your blood type?

The presence of particular antigens chooses ABO blood types:

  • Type A has A antigen
  • Type B has B antigen
  • Type O has neither A nor B antigen
  • Type AB has both A and B antigen

After you are aware about your ABO blood type, it can be defined by detecting Rhesus (Rh) factor:

  • Rh-positive – If you are having Rh antigens on red blood cells surface, you have Rh-positive blood.
  • Rh-negative – When you do not have the Rh antigens on red blood cells surface, you have Rh-negative blood.

By taking into consideration Rh factor, the 8 common blood types are: A+ or A-, AB+ or AB-, B+ or B- and O+ or O-.

How blood testing is usually done

The easiest way to find out your blood type is by conducting a test. The phlebotomist takes a needle to draw your blood from the hand or arm at the doctor’s clinic. The process for typing blood has two steps:

  • forward typing
  • reverse typing

Forward typing

The first step is what you call “forward typing.” The blood cells are combined together with the antibodies against type A and B blood. The blood sample will then be checked to know whether the blood cells stick together. When the blood cells merge together, your blood cells react with one of these antibodies.

For example, if the blood cells agglutinate when combined with the antibodies against type B blood, this means you have type B blood.

Reverse typing

The second step is known as “reverse typing” or “back typing.” The liquid part of the blood without the presence of red blood cells is combined with blood cells which are called type A and type B.

People who have type A blood also consist of antibodies against Type B blood in the serum. On the other hand, the ones having type B blood consist of antibodies against the Type A blood in the serum.

Type O blood has both anti-A and anti-B antibodies.

For example, if agglutination happens when the serum is combined with type B blood cells, this denotes you are having type A blood.

The nutshell about Rh typing

ABO testing consists of both forward and reverse typing. The result from forward typing is the blood type of patient. Similarly, reverse typing is a cross-check for forward typing and offers confirmation of the results.

Then your blood will be combined with anti-Rh serum. If the blood cells respond by merging together, this indicates you are having Rh-positive blood.

How to find out your blood type at home?

When it is about in at-home blood typing tests, you will have to prick your finger with a lancet and put drops of blood on special card.

After you put the blood on the card, you may watch the areas where blood spreads out or clumps and then match those reactions accordingly.

There are home testing kits available which have vials of fluid for the blood than a card.

How you will know your blood type for free

You can know your type of blood by donating blood.

When you want to donate to community blood supplies, ask the staff whether they can tell you about your type of blood. You will come across various donation centers that can give this information.

Typically, you will not get your blood type instantly and may even have to wait for some time.

How to determine your blood type without drawing blood

A good percentage of people have secreted blood group antigens into the other bodily fluids, such as sweat, mucus and saliva. This group of people is what you call secretors.

Secretors can determine their type of blood by saliva or other body fluid tests.

There are blood typing kits with saliva available online but they are very costly.

By using any of these kits, you will know whether you are a secretor. If you are, then you can know your ABO blood type.

There are several ways to determine your blood type and some of these are the following:

  • seeing a doctor
  • donating your blood
  • going to the hospital for testing blood
  • purchasing a home testing kit

Thus, if you belong to any of these groups of people who secrete blood-group antigens in other body fluids, you can determine your blood type without the need to draw blood. You can use search strings like, “blood type test near me,” when conducting a blood test to know your type in your specific area.