ABO Basics• Blood group antigens are

actually sugars attached to the red blood cell.

• Antigens are “built” onto the red blood cell.

• Individuals inherit a gene which codes for specific sugar(s) to be added to the red cell.

• The type of sugar added determines the blood group.

ABO Basics

• The immune system produces an antibody (protein) in the plasma (produced by white blood cells) for the antigen not present.

• Antibodies recognize foreigners and destroy them. Antibody B destroys antigen B.

• For example, blood type A has antigen A attached to the red blood cell and antibody B in their plasma. Therefore, if blood type B is injected into their systems, anti-B antibodies in their plasma will recognize it as an alien and destroy it.

http://upload.wikimedia.org/wikipedia/commons/3/32/ABO_blood_type.svg

Rh Factor• Another important antigen (antigen D) found on the

surface of blood cells is the Rh factor.• Blood containing this antigen is said to be Rh positive

(Rh+); blood lacking this antigen is said to be Rh negative (Rh-).

• For this reason all individuals are typed for D, if negative must receive Rh (D) negative blood.

Rh Disease of the Neborn – How it Occurs

• A) child is Rh + and mother is Rh -• B) during pregnancy fetal Rh + rbc’s escape into maternal circulation• C) This causes the mother's immune system to make antibodies against the baby's

red blood cells Rh (D) in future pregnancies. • D) Second pregnancy with Rh (D) pos child results in destruction of fetal D pos rbcs• This antibody response is called Rh sensitization and, depending on when it

happens, can destroy the red blood cells of the baby before or after it is born. • If sensitization happens, a fetus or newborn can develop mild to severe problems

(called Rh disease). In rare cases, if Rh disease is not treated, the fetus or newborn may die.

• A woman with Rh-negative blood can get a shot of Rh immunoglobulin (such as RhoGAM) that almost always stops sensitization from occurring. Problems from Rh sensitization have become very rare since Rh immunoglobulin was developed.

Hemolysis

• If an individual is transfused with an incompatible blood group destruction of the red blood cells will occur.

• This may result in the death of the recipient.

Clumping• If a film remains uniform in appearance, there

is no agglutination (clumping).• If the sample appears granular, agglutination

has occurred. What blood type does the person in the right have?

Anti-A Results

Anti-B Results

Anti-RH Results

Blood Type

Positive (+)

Negative (-)

Positive (+)

Negative (-)

Positive (+)

Negative (-)

When does the blood react?

• Blood reacting to anti-A is group A because it has antigen A.

• Blood reacting to anti-B is group B because it has antigen B.

• Blood reacting to both anti-A and anti-B is group AB because it has both antigen A and B.

• Blood not reacting to either anti-A or anti-B is group O because it has no antigens.

• Blood reacting to anti-Rh (D) is Rh+; Blood not reacting to anti-Rh (D) is Rh-

How common is your blood type?

46.1%

38.8%

11.1%

3.9%

Blood Transfusion

Type You Can Give Blood To

You Can Receive Blood From

A A,  AB A, O

O ALL O

B B,  AB B,  O

AB AB ALL

TYPE YOU CAN GIVE BLOOD TO

YOU CAN RECEIVE BLOOD FROM

Rh + + + or -Rh - + or - -

With Rh-/Rh+

Type You Can Give Blood To

You Can Receive Blood From

A+ A+  AB+ A+  A-  O+  O-

O+ O+  A+  B+  AB+ O+  O-

B+ B+  AB+ B+  B-  O+  O-

AB+ AB+ Everyone

A- A+  A-  AB+  AB- A-  O-

O- Everyone O-

B- B+  B-  AB+  AB- B-  O-

AB- AB+  AB- AB-  A-  B-  O-