Blood Type (ABO)
The Function of Antibodies
• Our bodies make antibodies to protect us from
“foreign” molecular species.
• Persons with A-antigens produce B-antibodies
(Anti-B) but not A-antibodies (Anti-A) since Aantigens are natural in their system.
The Function of Antibodies
• Likewise, persons with B-antigens produce Aantibodies (Anti-A) but not B-antibodies (Anti-B)
since B-antigens are natural in their system.
The Function of Antibodies
• Persons with A-antigens and B-antigens do not
produce A-antibodies (Anti-A) nor B-antibodies
(Anti-B) since both occur naturally in their
system.
Agglutination
• The clumping process that takes place when
RBCs containing a particular antigen (A or B) are
mixed with serum containing the antibody
specific for that antigen.
• The serum containing
the antibody is
called antiserum.
Agglutination
Blood Types and Serum Antibodies
Blood
Type
A
Antigens on
RBC
A
Antibodies in Serum
B
B
Anti-A
AB
AB
Neither anti-A or anti-B
O
Neither
A nor B
Both anti-A and anti-B
Anti-B
Blood Group Distribution in the
United States
•
•
•
•
43% O
42% A
12% B
3% AB
Other RBC Antigens
• There are more than 15 known RBC antigens
systems.
• The A-B-O system is commonly used in blood
typing.
• The Rh system is also used for blood types.
The Rh System
• Based on the Rh factor or D antigen.
• A person whose RBCs have the D antigen is
said to be Rh positive.
• Likewise, a person whose RBCs do not have
the D antigen is said to be Rh negative.
Blood Type Distribution in the
United States
Identification of Blood
with Known Antiserum
Anti-A Serum
+
Whole Blood
+
+
-
Anti-B Serum Antigen
+
Present
Whole Blood
A
+
B
+
A and B
Neither
A nor B
+ shows agglutination; - shows absence of agglutination.
Blood
Type
A
B
AB
O
Identification of Blood
with Known Cells
A Cells
+
Blood
+
+
-
B Cells
+
Blood
+
+
-
Antibody Present
Blood
Type
Anti-A
Anti-B
Anti-A and Anti-B
Neither Anti-A
nor Anti-B
B
A
O
AB
+ shows agglutination; - shows absence of agglutination.
Antiserum A, B, and Rh are Added
to a Blood Sample
• No agglutination
is occurring.
Antiserum A is Added to an A or AB
type Blood Sample
Antiserum B is Added to a
B or AB type Blood Sample
Antiserum Rh is Added to a Rh
positive Blood Sample
Name that Blood Type
Name that Blood Type