1. FORENSIC SEROLOGY
Forensic serology involves the detection, classification and study of various bodily fluids such as blood, semen, perspiration, and their relationship to a crime scene.
A forensic serologist may also be involved in DNA analysis and bloodstain pattern analysis.

2. The Nature of Blood
The word blood refers to a highly complex mixture of cells, enzymes, proteins, and inorganic substances.
Plasma, which is the fluid portion of blood, is composed principally of water.
Red blood cells (erythrocytes), white blood cells (leukocytes), and platelets are the solid materials suspended in plasma.
Antigens, usually proteins, are located on the surface of red blood cells and are responsible for blood-type characteristics.

3. Blood Typing
More than 15 blood antigen systems have been identified, but the A-B-O and Rh systems are the most important.
An individual that is type A has A antigens on his/her red blood cells, type B has B antigens, AB has both A and B antigens, and type O has neither A nor B antigens.
Rh factor is determined by the presence of another antigen, the D antigen.
People having the D antigen are Rh positive; those not having the antigen are Rh negative.
For every antigen there is a specific antibody that will react with it to form clumps known as agglutination.
Thus, if serum containing anti-B is added to red blood cells carrying B antigen, they will immediately react.

4. Blood Typing What’s Your Type? O+ 1 in 3 37.4% A+ 1 in 3 35.7%
B+        1 in 12        8.5%
AB+     1 in 29        3.4%
O-        1 in 15        6.6%
A-        1 in 16        6.3%
B-        1 in 67        1.5%
AB-     1 in 167        .6%

5. Blood Typing Compatible Blood Types O- can receive O-
O+ can receive O+, O-
A- can receive A-, O-
A+ can receive A+, A-, O+, O-
B- can receive B-, O-
B+ can receive B+, B-, O+, O-
AB- can receive AB-, B-, A-, O-
AB+ can receive AB+, AB-, B+, B-, A+,  A-,  O+,  O-

6. Blood Typing
There are four major blood groups determined by the presence or absence of two antigens – A and B – on the surface of red blood cells:
Group A – has only the A antigen on red cells (and B antibody in the plasma)
Group B – has only the B antigen on red cells (and A antibody in the plasma)
Group AB – has both A and B antigens on red cells (but neither A nor B antibody in the plasma)
Group O – has neither A nor B antigens on red cells (but both A and B antibody are in the plasma)

7. Blood Typing Compatible Plasma Types O can receive O, A, B, AB
A  can receive A, AB
B  can receive B, AB
AB  can receive A, B

8. Serology
The term serology is used to describe a broad scope of laboratory tests that use specific antigen and serum antibody reactions.
The identity of each of the four A-B-O blood groups can be established by testing the blood with anti-A and anti-B sera.
The concept of specific antigen–antibody reactions has been applied to immunoassay techniques for the detection of drugs of abuse in blood and urine.

9. Videos Is It Blood? https://www.youtube.com/watch?v=fxNR_I5IQtg
Forensic Serology: Blood Basics
Is It Blood?

10. Blood Spatter Analysis
Linda Stefaniak
Upper Freehold Regional School District
October 11, 2006

11. Stain Patterns of Blood
The crime scene investigator must remember that the location, distribution, and appearance of bloodstains and spatters may be useful for interpreting and reconstructing the events that produced the bleeding.
Surface texture and the stain’s shape, size, and location must be considered when determining the direction, dropping distance, and angle of impact of a bloodstain.
FORENSIC SEROLOGY

12. Stain Patterns of Blood
Surface texture is of paramount importance. In general, the harder and less porous the surface, the less spatter results.
The direction of travel of blood striking an object may be discerned because the pointed end of a bloodstain always faces its direction of travel.
The impact angle of blood on a flat surface can be determined by measuring the degree of circular distortion. At right angles the blood drop is circular, as the angle decreases, the stain becomes elongated.
The origin of a blood spatter in a two-dimensional configuration can be established by drawing straight lines through the long axis of several individual bloodstains. The intersection or point of convergence of the lines represents the origin point.
FORENSIC SEROLOGY

13. Bloodstain Pattern Analysis (BPA)
While the use of bloodstains as evidence is not new, the application of modern science has brought it to a higher level.
New technologies (DNA analysis) are available for detectives and criminologists to use in solving crimes and apprehending offenders.

14. Bloodstain Pattern Analysis (BPA)
BPA applies scientific knowledge from other fields to solve practical problems.
Draws from biology, chemistry, math and physics
Produces strong, solid evidence

15. BPA can determine:
Location and description of individual stains and patterns
Mechanism that created the stains
Direction a blood droplet was traveling
Area of origin
Type of object used in attack
Minimum number of blows
Presence of a subject at a scene
Positioning of the victim, suspect and objects during events
Sequence of events

16. Determining angles of impact
Blood droplets in freefall have the shape of a sphere.
Droplets striking surfaces and leaving well-formed stains make it possible to determine the angle at which the droplet struck the surface.

17. Determining angles of impact
A well-formed stain is in the shape of an ellipse
The ratio between the length-width of the ellipse is the function of the sine of the impact angle
Accurately measuring the stain gives this impact angle

18. Point and area of convergence
The point of convergence is the intersection of two bloodstain paths, where the stains come from opposite sides of the impact pattern

19. Point and area of convergence
The area of convergence is the box formed by the intersection of several stains from opposite sides of the impact pattern.

21. Point and area of convergence
Point (Area) of Origin – the common point (area) in three dimensional space to which the trajectories of several blood drops can be retraced.

22. Target surface texture
Bloodstains can occur on a variety of surfaces, such as carpet, wood, tile, wallpaper, clothing…..
The type of surface the blood strikes affects the amount of resulting spatter, including the size and appearance of the blood drops.

23. Target surface texture
Blood droplets that strike a hard smooth surface, like a piece of glass, will have little or no distortion around the edge.

24. Target surface texture
Blood droplets that strike linoleum flooring take on a slightly different appearance.
Notice scalloping around the edge of the blood droplets.

25. Target surface texture
Surfaces such as wood or concrete are distorted to a larger extent.
Notice the spines and secondary spatter present.

26. Blood Drops vs. Angle on Manila Folder

27. Blood Drops vs. Angle on Paper

28. Bloodstain pattern categories
Classifies stains based on the mechanism that created them.
Passive bloodstains are created when the force acting on the blood is gravity
Projected bloodstains occur when some form of energy has been transferred to a blood source
Transfer or contact is produced when an object with blood on it comes into contact with an object or a surface that does not have blood on it.

29. Passive drops
A bloodstain drop(s) created or formed by the force of gravity acting alone.

30. A bloodstain pattern that results from blood dripping into blood
Drip pattern
A bloodstain pattern that results from blood dripping into blood

31. Flow pattern
A change in the shape and direction of a bloodstain due to the influence of gravity or movement of the object

32. Low Velocity Impact (LVI)
Relatively large stains 4 mm in size and greater. Impact velocity up to 5 feet/sec

33. Medium Velocity Impact (MVI)
Preponderant stain size 1 to 4 mm size.
Impact velocity of 5 to 25 feet/sec.

34. Impact velocity of 100 feet/sec and greater.
High Velocity Impact (HVI)
Preponderant stain size 1 mm in size and smaller. Mist like appearance.
Impact velocity of 100 feet/sec and greater.

35. Cast-off pattern
A bloodstain pattern created when blood is released or thrown from a blood-bearing object in motion

36. Arterial spurting or gushing
Bloodstain pattern(s) resulting from blood exiting the body under pressure from a breached artery

37. Back spatter and expiratory blood
Back spatter – blood directed back towards the source of energy or force that caused the spatter
Expiratory blood – blood that is blown out of the nose, mouth or a wound as a result of air pressure and/or air flow which is the propelling force

38. Swipe pattern
The transfer of blood from a moving source onto an unstained surface. Direction of travel may be determined by the feathered edge.

39. Hair swipe pattern
The transfer of blood from a moving source onto an unstained surface. Direction of travel may be determined by the feathered edge.

40. Wipe pattern
A bloodstain pattern created when an object moves through an existing stain, removing and/or altering its appearance.

41. Transfer pattern
A bloodstain pattern created when a wet, bloody surface comes in contact with a second surface. A recognizable image of all or a portion of the original surface may be observed in the pattern.
When a wet bloodied object comes in contact with a non-bloodied surface, some blood will be transferred from the object to the surface. In some cases the resulting transfer pattern may have enough detail to identify the object that created the stain.

42. Transfer pattern
A bloodstain pattern created when a wet, bloody surface comes in contact with a second surface. A recognizable image of all or a portion of the original surface may be observed in the pattern.
When a wet bloodied object comes in contact with a non-bloodied surface, some blood will be transferred from the object to the surface. In some cases the resulting transfer pattern may have enough detail to identify the object that created the stain.

43. Video Blood Spatters 101 (7:09)
Blood Spatters 101
(7:09)

44. Sources BPA Tutorial http://www.bloodspatter.com/BPATutorial.htm
Blood Pattern Analysis (Wikipedia, I kid you not!) at_crime_scenes
International Association of B. P. Analysts

45. Knowledge Check
List three factors that determine the appearance of a passive blood drop.
surface texture
direction of travel of blood
impact angle

46. Adult tissue (adult stem cells).
Knowledge Check
What are “stem cells?”
Stem cells are a class of undifferentiated cells that are able to differentiate into specialized cell types. Commonly, stem cells come from two main sources:
Embryos formed during the blastocyst phase of embryological development (embryonic stem cells) and
Adult tissue (adult stem cells).
Both types are generally characterized by their potency, or potential to differentiate into different cell types (such as skin, muscle, bone, etc.).

47. List some things that BPA can determine.
Knowledge Check
List some things that BPA can determine.
Location and description of individual stains and patterns
Mechanism that created the stains
Direction a blood droplet was traveling
Area of origin
Type of object used in attack
Minimum number of blows
Presence of a subject at a scene
Positioning of the victim, suspect and objects during events
Sequence of events

48. In BPA studies, what is meant by the “point of convergence?”
Knowledge Check
In BPA studies, what is meant by the “point of convergence?”
the intersection of two bloodstain paths, where the stains come from opposite sides of the impact pattern

49. What can you say about this blood drop?
Knowledge Check
What can you say about this blood drop?
Blood droplets that strike a hard smooth surface, like a piece of glass, will have little or no distortion around the edge.

50. What can you say about this blood drop?
Knowledge Check
What can you say about this blood drop?
Surfaces such as wood or concrete are distorted to a larger extent. Notice the spines and secondary spatter present.

51. Knowledge Check What can you say about this blood drop?
Impact velocity of 100 feet/sec and greater