1. Blood Evidence
Chapter 10

2. Serology
Study of bodily fluids
Saliva
Semen
Urine
Blood

3. 2 tests for blood at crime scene
1. Presumptive Test
Tests if blood is present
2. Precipitin Test
Tests if blood is human or animal

4. Luminol
Use on areas that may have been cleaned, reacts with hemoglobin in blood

5. CSI: Miami

6. Blood is made up of 4 parts
Plasma: Fluid part of the blood
Red blood cells: carry oxygen, determine blood type
White blood cells: fight infection, can contain DNA
Platelets: for blood clotting

8. Class vs. Individual Blood type is CLASS evidence
DNA is INDIVIDUAL evidence
Blood spatter is circumstantial evidence

9. Blood facts Human body has 5 liters of blood
1 billion red blood cells in a drop of blood
For every 600 red blood cells there are 40 platelets and 1 white blood cell

10. How common are the 4 blood types?
What are blood types?
There are 3 alleles or genes for blood type: A, B, & O. Since we have 2 genes, there are 6 possible combinations.
45%
40%
11% 4%
How common are the 4 blood types?

11. 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-).
Rh+ = 85%
Rh- = 15%
A+ A- B+ B- AB+ AB- O+ O-

12. Genotypes & Phenotypes: Remember biology freshman year?
AA or AO
Type A
BB or BO
Type B AB
Type AB OO
Type O

13. More vocabulary
Antigen: proteins on the red blood cell, give the cell its type
Antibody: immune proteins that are in your blood that attack foreign substances
Agglutination: when blood type testing, this is when there is clumping (if antigen and antibody match)

14. 14. Use the results shown to determine the blood type for each sample.
Blood Typing
14. Use the results shown to determine the blood type for each sample.
- = No Clumps
+ = Clump A B Rh
Blood Type: ___
To determine a person’s blood type, we add three different serums to blood samples and see if clumps form.
Clumps = Positive (+) No Clumps = Negative (-) What would the blood type be for this sample?
#13

15. - = absent + = present Blood TypingRh
Blood Type: ___ A B Rh
Blood Type: ___
Blood Typing
Use the results shown to determine the blood type for each sample. A B Rh
Blood Type: ___ A B Rh
Blood Type: ___ A B Rh
Blood Type: ___
- = absent
+ = present

16. How can blood be used as EVIDENCE?
Blood samples – Can be analyzed to determine BLOOD TYPE and DNA, which can be matched to possible suspects.
Blood droplets – Can be analyzed to give clues to the location of a WOUND, MOVEMENT of a victim, and type of INJURY.
Blood spatter – Can be analyzed to determine PATTERNS that give investigators clues to how a crime might have happened.

17. Assignment Using the notes you just took: Create a 15 question quiz
Collect
Randomly hand out to complete
Each quiz should have 2 names: the creator and the quiz taker
Due at end of class