Blood Type

WHAT IS A BLOOD TYPE?
When your practitioner tells you your "blood type," you are being given two pieces of information - your blood group and your Rh status.

 

a. Your blood group will be A, B, AB, or O. If you have "A" "B" or "O" blood group, you have antibodies in your blood plasma that destroy some of the other blood groups. If you have group "A" blood, you cannot receive blood that is group "B" and vice versa. If you have "O" blood, your body will create antibodies to fight "A" or "B" blood. If you have group "AB" blood however, your body will not create antibodies for any of the other blood groups.

 

b. Your Rh status will be listed as negative (-) or positive (+). If you have Rh- blood, your body may form antibodies against Rh+ blood and destroy it. In order for this to happen, you must first be exposed to Rh+ blood (i.e., through a blood transfusion or carrying an Rh+ fetus). This can be a problem if you have antibodies against Rh+ blood and are pregnant with an Rh+ fetus. However, there is medication that can prevent this reaction from occurring if it is given immediately after you are exposed to Rh+ blood.

TO WHOM CAN I DONATE BLOOD, AND FROM WHOM CAN I RECEIVE BLOOD?

Group	If you are:	You can donate to:	You can receive from:
	*O	A, B, AB, O	O
	A	A, AB	O, A
	B	B, AB	O, B
	** AB	AB	A, B, O, AB
Rh status	Rh +	Rh +	Rh +, Rh -
	Rh -	Rh +, Rh -	Rh -

* Universal donor

** Universal receiver

 

While knowing your blood type can be useful information, a transfusion of blood cells is never done unless your blood is rechecked for blood type and tested with the donor blood in order to ensure that it is compatible.

 

WHAT BLOOD TYPE WILL MY CHILDREN BE?
Inheritance of blood type can be complicated. You may have group "A" blood, but have genes for both groups "A" and "O." Because "A" group is stronger or dominant, your blood will be group "A." However, you can give your children genetic material for either group "A" or "O." The same is true of "B" group. If both "A" and "B" genetic material is given to your child, the child will have group "AB" blood. A child with genes for "O" from both parents will be group "O." The chart on the following page shows this pattern.

 

Father's group		Mother's group
		O	A	B	AB
	O	O	O, A	O, B	A, B
	A	O, A	O, A	O, A, B, AB	A, B, AB
	B	O, B	O, A, B, AB	O, B	A, B, AB
	AB	A, B	A, B, AB	A, B, AB	A, B, AB

 

Rh status is similar to blood groups. If you are Rh positive, you may have genes for both positive and negative. If you are Rh negative, you have two genes for Rh negative.

 

		Mother's group
		Rh +	Rh -
Father's group	Rh +	Rh +, Rh +	Rh +, Rh -
	Rh -	Rh +, Rh -	Rh -

 

Source

U.S. Department of Health and Human Services (1981). Medicine for the Layman, Blood Transfusions: Benefits and Risks, 81-1949. National Institutes for Health.