1. FORENSIC SEROLOGY
Chapter 12

2. Blood Plasma - the liquid portion of the blood
A complex mixture of cells, enzymes, proteins & inorganic substances
Plasma - the liquid portion of the blood
Cellular portion of blood contains
red cells (erythrocytes, RBCs) – carry O2
white cells (leukocytes, WBCs) – fight infection
Platelets (thrombocytes) – used for clotting

3. Blood Properties Blood: Accounts for about 8 % of total body weight.
5 to 6 liters of blood for males.
4 to 5 liters of blood for females.
A 40 percent blood volume loss, internally or/and externally, is required to produce irreversible shock (death)

4. Red Blood Cells Most abundant cells in the blood
Give blood its characteristic red color.
Account for 40 to 45% of the blood. The percentage of blood made up of RBCs is often measured and is called the hematocrit.
The ratio in normal blood is:
600 RBCs for every 1 white blood cell and 40 platelets.
There are several things about RBCs that make them unusual:
Has a strange shape
Has no nucleus.
Can change shape to an amazing extent, without breaking, as it squeezes single file through the capillaries.
Contains hemoglobin

5. Erythrocytes (RBC)
Red cells possess chemical structures on their surfaces called antigens or agglutinogens
Impart blood type characteristics

6. White Blood Cells Platelets
Part of the immune system and fight infection.
Circulate in the blood to be transported to an infection site.
In a normal adult body there are 4,000 to 10,000 WBCs per microliter of blood.
Platelets
The clotting factors that are carried in the plasma
They clot together in a process called coagulation to seal a wound and prevent a loss of blood.

7. Plasma Clear, yellowish fluid
Can sometimes appear milky after a very fatty meal or when people have a high level of lipids in their blood.
Contains electrolytes, nutrients and vitamins, hormones, clotting factors, and proteins such as antibodies to fight infection.
Plasma is 90-percent water. The rest is protein.

8. Blood Clotting
Blood Clot Formation (blood cells, platelets, fibrin clot)

9. What is Serology?
The study of the proteins found in blood, used in forensics will focus on the antigen / antibody protein connection to determine blood typing

10. Blood Types Karl Landsteiner, 1900
Noted that when blood from different people was mixed it sometimes forms a precipitate - deadly if mixed in body.
Explored why.
Blundell's blood transfusion apparatus, 19th century

11. Genetics of Blood Types
Your blood type is established before you are BORN, by specific GENES inherited from your parents.
You inherit one gene from your MOTHER and one from your FATHER.
These genes determine your blood type by causing proteins to exist on the surface of all of your red blood cells.

12. AA or AO = Type A BB or BO = Type B OO = Type O AB = Type AB
What are blood types? (ABO system)
There are 3 alleles or genes for blood type: A, B, & O.
Since we have 2 genes, there are 6 possible combinations (genotypes)
Blood Types
AA or AO = Type A BB or BO = Type B OO = Type O AB = Type AB

13. Blood Types - Paternity
And the Father Is: A B AB O
If the Mom is:
A or O
A, B, AB, or O
A, B, or AB
The Child Must Be:
A, B, AB or O
B or O
A, B or AB
A or B

14. Antibodies Proteins that are present in the serum
Responsible for ensuring that the only blood cells that can survive in a person are cells of the correct blood type
Antibodies produced by the A alleles remove cells containing B antigens by clumping them together
Antibodies produced by the B alleles remove cells possessing A antigens

15. Immunoassay: A technique utilizing antibodies to bind specifically to targeted substances in order to identify their presence

16. Type O Blood Possessed by people whose genotype is OO
both parents passed on the O gene
have no antigens
can be introduced into a person with Type A or Type B because the cells are not attacked by antibodies
have both A & B antibodies
can only have other O type cells mixed with this blood

17. Type A Possessed by people with genotype AA AO A is dominant to O
Possesses antibody B
will destroy any Type B red cells

18. Type B Possessed by people with genotype BB BO B is dominant to O
Possesses antibody a
will destroy any Type A red cells

19. Type AB Possessed by people with genotype AB A & B are co-dominant
Possesses no antibody
can have A, B, AB, or O cells added
Can’t be added to any other blood type without being destroyed by an antibody

20. Blood Typing
Blood typing is done by reacting whole blood with antibody A and antibody B

21. Blood Typing

22. Rh Factors A+ A- B+ B- AB+ AB- O+ O-
While studying Rhesus monkeys, a certain blood protein was discovered. This protein is also present in the blood of some people. Other people, however, do not have the protein.
The presence of the protein, or lack of it, is referred to as the Rh (for Rhesus) factor.
If your blood does contain the protein, your blood is said to be Rh positive (Rh+). If your blood does not contain the protein, your blood is said to be Rh negative (Rh-).
A+ A- B+ B- AB+ AB- O+ O-

23. How common is your blood type?
46.1%
38.8%
11.1%
3.9%

24. Blood Transfusions O A B AB
A blood transfusion is a procedure in which blood is given to a patient through an intravenous (IV) line in one of the blood vessels. Blood transfusions are done to replace blood lost during surgery or a serious injury. A transfusion also may be done if a person’s body can't make blood properly because of an illness. A B O AB
Universal Donor
Universal Recipient

25. Who can give blood?
Type O- called the universal donor because it can be given to anybody; it has no protein to cause clumps (coagulation).
Type AB+ is the universal receiver because the recipient has all of the proteins and so will not form clumps (coagulation).
Rh +  Can receive + or -
Rh -  Can only receive -

26. Forensic Blood Analysis
Identification (“Is it blood”?)
Blood origin (human or other source?)
Blood Type
Blood Spatter Analysis

27. Identification (“Is it blood”?)
Hemoglobin has peroxidase-like activity (enzymes that accelerate oxidation of organic compounds).
Kastle-Meyer Test - uses phenolphthalein (an acid/base indicator)
Blood + phenolphthalein + peroxide (H2O2) → deep pink color
Can give false positives (horseradish, some vegetables, potatoes, etc.)

28. Identification (“Is it blood”?)
Luminol Test: Reaction of luminol w/ blood produces a complex which can be seen by luminescence.
Very sensitive
Detects unseen samples and patterns.
Does not interfere with later DNA testing.

29. Blood origin (human or other source?)
Precipitin Test
Animals are injected with human blood to form antibodies
Isolate human antiserum (antibodies to human blood)
Human antiserum will react with human blood.
Antiserum can be made similarly for many other animals
Works on old (dried for many years) and small samples of blood

30. Blood Spatter Analysis
The examination of the shapes, locations, and distribution patterns of bloodstains, in order to provide an interpretation of the physical events which gave rise to their origin.
Used to:
Confirm or refute assumptions concerning events
Position of victim (standing, sitting, lying). Evidence of a struggle. (blood smears, blood trails)
Confirm or refute statements made by people involved in the case:
Are stain patterns on a suspects clothing consistent with his reported actions? Are stain patterns on a victim or at a scene consistent with accounts given by witnesses or the suspect?

31. Bloodstain Evidence Direction from which blood originated
Angle of impact
Location or position of a victim when wound was inflicted
Movement of a bleeding individual
Number of blows that struck a bleeding victim
Approximate location of an individual delivering blows

32. Bloodstains – 3 patterns
Projected
Passive
Transfer

33. Passive Bloodstains
Drops created or formed solely by the force of gravity.
Can be subdivided:
Drops
Drip patterns
Pools
Clots

34. Surface Bloodstains (Passive)
Type of surface the blood strikes affects the spatter pattern.
Blood droplets that strike a hard smooth surface will have little distortion around the edges
Blood droplets that strike linoleum flooring will often show small distortion around the edges
Blood droplets striking wood, carpeting or concrete are distorted to a larger extent (ex. spines, satellites spatter)
Smooth Linoleum Concrete

35. Effect of Target Surface. .
Effect of Target Surface .
Spreads out smoothly
ST of spreading edge is
broken by irregular surface

36. Transfer Bloodstains
Created when a wet, bloody surface comes in contact with another surface
Occasionally, a recognizable image of the original surface may be observed, such as a hand or shoe pattern.
Subdivided:
Contact bleeding
Swipe or Smear
Wipe
Smudge.

37. Projected Bloodstains
Created when a blood source is subjected to an action greater than the force of gravity
The size, shape, and number of resulting stains will depend on the amount of force utilized to strike the blood source

38. Types of Projected Bloodstains
Arterial Spurt / Gush - from blood spurt under pressure from a cut artery
Cast-off Stains - blood released or thrown from a blood-soaked object in motion
Impact Spatter - created when a blow or force results in the random dispersion of smaller drops of blood
Arterial Cast-Off

39. Projected Bloodstains - Impact
Low Velocity - Gravitational pull. Relatively large stains 4 mm and greater.
Medium Velocity - Stain size 1 to 4 mm.
High Velocity - Stain size 1 mm and smaller (Mist like appearance).
Low Medium High

40. . Wave Cast-off Tail of elongated stain points in direction of travel
Tail of wave cast-off points
back to parent drop
Parent drop
wave cast-off

41. Downswing of Hammer

42. Cast-off from Weapon
ceiling

43. Cast off Pattern Sequence1
(4 spots) 2
(3 spots) 3
(2 spots)
If weapon does not pick up more blood, spatter from subsequent backswings becomes progressively less.
In practice weapon picks up more blood with each successful blow.

44. DIRECTIONALITY OF BLOODSTAINS
When a droplet of blood strikes a surface perpendicular (90 degrees) the resulting bloodstain will be circular.  
Blood that strikes  a  surface at an angle  less than  90 degrees will be elongated or have a tear drop shape.
Directionality is usually obvious as the tail will always point in the direction of travel.

45. IMPACT ANGLE DETERMINATION
ANGLE of IMPACT (AOI) is the acute angle formed between the direction of the blood drop and the plane of the surface it strikes
By utilizing trigonometric functions its possible to determine the impact angle for any given blood droplet.
SIN θ = opposite
              hypotenuse

46. Blood Spatter
SIN Ө = Width  (a) = 1.5 cm
               Length (c) cm

47. Point of Convergence (origin determination)
2 Dimensional Analysis

48. Point of Convergence (origin determination)
3 Dimensional Analysis –
String method