Blood Types
Anti-Serums & Chemical Tests
Blood Drops
Blood Patterns
Blood Patterns 2
100
What type of blood cell carries the proteins that determine blood type?
Red Blood Cells!
100
You want to know if B protein is present in a blood sample. Describe how you would find out.
Add anti-B serum to the sample. If the blood clumps, the protein is present.
100
What are ‘spines’ on a blood drop? What condition would cause drops to form many spines?
Spines radiate out from a blood drop, when it falls - more spines if it falls from a greater distance, more spines when it falls on a hard surface.
100
A bloody handprint on the wall. What type of bloodstain pattern is this?
Transfer pattern
100
Describe Low Velocity blood patterns, how are they formed?
Drops or pools of blood, formed when blood falls due to gravity (no force applied) also known as Passive blood stains
200
Name the three proteins that may be found in a blood sample that determine blood type.
A protein, B protein, D (Rh) protein
200
If the blood clumps with anti-B, does this mean the blood type is B? Explain.
It means there is B protein present in the blood - but there also could be A, and/or Rh. So the blood type could be B-, B+, AB- or AB+
200
What are ‘satellites’ in a spatter pattern? What condition would cause drops to form many satellites?
Satellites are tiny drops of blood that spring out of the main drop due to force of impact. Dropping from greater distance, and especially dropping into a pool of blood.
200
Something smeared through blood on the floor. What type of bloodstain pattern is this?
Wipe Pattern
200
Describe the appearance of High Velocity spatter. What usually causes it?
Blood drops are very small, a mist of blood, usually caused by gunshot
300
Name the blood type proteins found in a person’s blood who is O-
O- blood type has none of the blood type proteins!
300
What blood type is this? Explain how you know.
The anti-A serum causes clumping, so we know there is A protein in the blood. There was no clumping for B or Rh, so the blood type is A -
300
BONUS
BONUS
300
What blood stain pattern are the drops of blood?
Low velocity (passive)
300
Come and place your hand on the approximate location the victim was when he was attacked.
17
400
Blood type is ________ Evidence!
Class
400
What is the purpose of a Presumptive Test?
To determine if a stain is blood or not blood. (could be animal blood!)
400
As the angle of impact for a blood drop becomes smaller, the shape of the drop…
As the angle decreases the drop becomes more elongated
400
Is cast off blood pattern an example of high, medium, or low velocity blood spatter?
Medium
400
Describe Medium Velocity spatter patterns. How are they formed?
Medium Velocity patterns are drops that are flung with force against a surface (wall, floor, ceiling, etc). Drops may come directly from a victim during an attack (drops fan out from central location), or fling off of the weapon
(trail/line of blood drops).
500
What blood type is most common?
O+
500
What is the purpose of chemical treatments such as Luminol, Fluorescein, and Leuco Crystal Black?
These chemicals are applied to find latent blood stains (stains that cannot be seen with the eye)
500
You have measured the angle of five different drops in the corner walls of a room. Describe how to use this information to determine where the victim was standing.
Extend lines out from each drop (using lasers or string) at the calculated angle. The lines will cross at the approximate location of the victim when attacked.
500
What is cast off, how is it produced?
When a person is attacked with a weapon, blood will cover the weapon and fling off of it, creating a trail of blood for each swing.
500
What else causes high velocity spatter? How can you tell the difference?
Expository blood out of mouth or nose, will have salivary secretions mixed into the blood