2. Composition
The word blood
refers to a mixture
of cells, enzymes,
proteins, and
inorganic
substances.
3. The fluid portion of the blood is called
the plasma and makes up 55% of
blood’s composition
Within the plasma are the solid
components such as red blood cells,
white blood cells, and platelets; this
makes up 45% of the composition.
4. Antigens
On the surface of each blood cell are
millions of chemical structures called
antigens
These antigens are responsible for
blood types of the RBC’s
5. Blood types
There are more than 15 blood type
systems that have been identified to
date and of those the A-B-O and Rh
systems are the most important.
Blood types are:
A, B, O, and AB
Those can be Rh+ or Rh- (also known as
antigen D)
6. Blood type distribution
Blood types are different in distribution
throughout different populations but in
the USA the percentages are:
O 43% Rh+ 85%
A 42% Rh- 15%
B 12%
AB 3%
7. Calculating Blood Types
Type O+
.43 X .85 = .3655
.3655 X 100% = 36.55% of the
population is type O+
8. Phenotype for blood type
If an individual is A blood type that
means the individuals red blood cells
have A antigens located on the
surface…same with type B
Type AB has both antigens
Type O has neither antigens
The presence of type D antigen
indicates Rh + and the lack of D
indicates Rh -
10. Antibodies
For every antigen there is a specific
antibody and an antibody will react only
with a specific antigen
If a serum containing antibody B, anti-B
for short, is added to blood containing
antigen B then a agglutination or clotting
will occur
11. Testing for Blood type
When testing for blood type of an unknown
source, Anti-A and Anti-B sera are used to test
for agglutination as follows
Anti-sera A Anti-sera B Antigen present Blood type
+ - A A
- + B B
+ + A and B AB
- - Neither O
