ABO Blood Types


ABO Blood Types

Another example of the geneprotein connection

Blood Typeswhat’s the difference?

How is it determined?

Blood sample is taken from a person and a small amount is placed in a well tray or on absorbent paper.

Technician looks for

“agglutination” (aka: clumping or precipitate).

Clumps with Anti-A antibodies?

Must have A proteins

Could be Type A or Type AB


What causes clumping?

The anti-A antibodies have a shape that matches the A protein.

The antibodies latch onto the Type A RBC and cause the cells to clump together.

Phenotype = Type A

Genotype = I



A or I

A i

Blood Donation & Transfusions

Has RBC with

B proteins

Has Anti-A antibodies in the plasma

Anti-A antibody

Type A



A antibodies in the plasma “attack” the Type A cells that are transfused into the bloodstream. Causes clumping. Not


Blood Donation & Transfusions

• So the person with Type B blood can receive blood of a type that



A proteins on the RBC.

• Type B RBC and Type O RBC won’t have

A proteins, so the Type B person can receive either Type B or Type O blood.

Blood Donation Chart

Type O can’t receive any other blood type.

Type AB can receive all other blood types.