Blood Type Testing

Knowing their blood type can help a person better understand their health and be more informed about potential treatments.
The presence or absence of substances called antigens helps determine blood type. Antigens are involved in triggering the body’s immune response.
A person may have A antigens, B antigens, both, or neither on the surface of their red blood cells. They may also have a protein called the Rhesus (Rh) factor.
The first stage in identifying blood type involves a test called ABO typing. This will determine which of the following four main blood types a person has:
A: the presence of just the A antigen
B: the presence of just the B antigen
AB: the presence of both antigens
O: the presence of neither antigen
The second stage involves identifying the presence ( ) or absence (-) of the Rh factor in the person’s blood.
Incorporating the four ABO types and the two Rh types, there are eight common blood types:
A
A-
B
B-
AB
AB-
O
O-
How to find out your blood type at home
A person usually visits a clinic or doctor’s office to find out their blood type. There, a doctor or nurse draws a blood sample and sends it to a lab for testing.
However, there are ways of determining blood type at home.
By drawing blood
A person can identify their blood type at home using a rapid blood typing kit.
Using the kit requires a person to prick a finger with a needle. The kit comes with a card that contains chemicals known as reagents. These test for the presence of the antibodies and Rh factor.
When one or more of the blood type antibodies or the Rh factor is present in the blood sample, the test produces a “clumping” of the blood. Typically, if clumping does not occur, the person’s blood type is O-negative
A person can purchase a home testing kit online.
Without drawing blood
A person may be able to use a saliva sample to test for their blood type, as some people produce the characteristic antigens in their saliva.
According to 2018 research, if a person does secrete these antigens in their saliva, a sample of dried saliva can reliably indicate their blood type.
However, it is important to note that not everyone secretes these antigens, and this method does not necessarily indicate the presence or absence of the Rh factor.
Are blood types inherited?
A person’s blood type is inherited from their biological parents.
A parent with type A blood can either pass on the A antigen or no antigen at all. If the other parent has type B blood, they can pass on the B antigen or no antigen. Depending on the combination, their child could have A, B, AB, or O blood.
If both parents have O blood, the child can only have O blood.
The Rh factor is inherited in the same way.