Blood

1
Blood
Out damned spot! Out, I say Heres the smell
of the blood still, All the perfumes of Arabia
will not Sweeten this little hand. Oh, Oh,
Oh! William Shakespeares Lady Macbeth, in
Macbeth
2
Unknown Stains at a Scene

• Questions to be answered
• Is it blood?
• Is it human blood?
• Whose is it?
• Determine blood type.
• What caused the blood spatter?
• Determine the method(s) in which blood may have
  been deposited.

3
Introduction

• Blood typing can provide class evidence whereas
  DNA profiling can provide individual evidence.

4
Blood Characteristics

• Whole blood carries cells and plasmathe fluid
  with hormones, clotting factors, and nutrients.
• Shown below
• Red (Erythrocyte) blood cells carry oxygen to
  the bodys cells and carbon dioxide away.
• Platelets aid in blood clotting and the repair
  of damaged blood vessels.
• White (Leukocyte) blood cells fight disease and
  foreign invaders and, alone, contain cell nuclei.

Erythrocyte Platelet Leukocyte
5
Blood Typing

• What are the four types of blood?
• A, B, AB, and O
• What do we use to identify the blood types?
• ABO Blood Typing
• What is the population distribution in the US?

6
Blood Typing

• What is the difference between the types?
• Antigen cells are located on the red blood
  cell.
• Antibodyare proteins secreted by white blood
  cells that attach to antigens to destroy them,
  located outside the red blood cell.
• Agglutinationclumping of red blood cells will
  result if blood types with different antigens are
  mixed

7
Blood Group A

• Has A antigens on the surface of red blood cells
  and B antibodies in blood serum.
• The B antibodies will attack and destroy Type B
  blood cells when they are introduced into the
  body.
• Can give blood to A and AB, can received blood
  from O and A

8
Blood Group B

• Has B antigens on the surface of red blood cells
  and A antibodies in blood serum.
• The A antibodies will attack and destroy Type A
  blood cells when they are introduced into the
  body.
• Can give blood to B and AB can receive blood
  from O and B

9
Blood Group AB

• Has both A B antigens on the surface of red
  blood cells NO A or B antibodies in blood
  serum.
• Will not reject or attack any blood types
  Universal Recipient
• Can give blood to AB, can receive blood from A,
  B, O, and AB

10
Blood Group O

• Has NO A or B antigens on the surface of red
  blood cells but has BOTH A B antibodies in
  blood serum.
• Will not provoke and attack by any antibodies
  Universal Donor
• Can give blood to A, B, O, and AB can receive
  blood from O

11
Blood Groups
Can Give Blood To
Can Get Blood From
Antigen
Type
Antibody
A
A
B
A, AB
O, A
B, AB
O , B
B
B
A
Neither A nor B
AB
A and B
AB
A, B, O, AB
Universal Acceptor
Neither A nor B
A, B, O, AB
O
A and B
O
Universal Donor
12
Rh Factor

• A certain blood protein was discovered while
  studying Rhesus Monkeys called Rh
• If this protein is present in your blood, you
  
• are Rh (positive).
• If your blood lacks this protein, you are
  
• Rh- (negative).
• This is why we have positive (O) and negative
  (B-) blood types!

13
Presumptive Tests forBlood Determination

• Kastle-Meyer color testa mixture of
  phenolphthalein and hydrogen peroxide the
  hemoglobin will cause the formation of a deep
  pink color if blood is present
• Hematest tabletreacts with the heme group in
  blood causing a blue-green color
• Luminol testreaction with blood to produce light

14
Human vs Animal Blood

• Microscopic observation
• RBC in animal has a nucleus
• RBC in human no nucleus

Frog Blood
Human Blood
15
Human vs Animal Blood

• Precipitin test
• Blood is injected into a rabbit antibodies are
  formed the rabbits blood is extracted as an
  antiserum the antiserum is placed on sample
  blood. The sample will react with human proteins
  if human blood is present. This test is very
  sensitive and requires only a small amount of
  blood.