1. Blood and Other Bodily fluids
Looking at blood
Forensics and Blood
Paternity
Other Bodily fluids

2. Who studies blood? Serologists!!
Bloods parts:
Leucocytes - WBC’s
Erythrocytes - RBC’s
Platelets – cells involved in clotting
Serum – yellowish liquid that remains after clot is removed
Contains most of the proteins and enzymes of the plasma

3. Looking at Blood – ABO system
RBC’s contain antigens – determine blood type
Antigens can be A or B
People with type A blood have A antigens
People with type B blood have B antigens
People with type AB blood have A and B antigens
People with type O blood do not have antigens

4. Rhesus Rh factor- another antigen in blood
Sometimes called the D factor
If present in your blood then blood type is Rh Positive
If not present blood type is Rh negative
So if a person has A positive blood what is in it?

5. Antibodies and Blood Type
Serum contains specialized proteins called antibodies
For every antigen there is a corresponding antibody
Antibodies are specific so they only react with one type of antigen
When the two combine they for a antigen-antibody complex
This is how we figure out blood type

6. Antigen-Antibody Chart

8. Identifying the Stain:
3 main questions must be asked:
Is it blood?
Is it human?
Whose blood is it?
To answer these questions one must have a sample in good enough condition
Putrefaction – the degrading of blood samples due to bacterial growth
Bacteria like warm wet environment
Dry samples are better to work with because they are less likely to be damaged

9. IS IT BLOOD? Testing the Stain
2 types of tests:
Presumptive
Cheaper and faster
Tell us that blood is likely present but not a fact
Used to rule out stains so we don’t waste time and money on testing a stain that is not actually blood
Confirmatory
Much more expensive and time consuming
Tell us beyond a doubt that blood is present
Only used once presumptive tests prove there is blood present

10. Presumptive Tests Kastle-Meyer Color Test Tetramethylbenzidine (TMB)
Uses phenolphthalein and hydrogen peroxide to see if blood is present
Phenolphthalein will turn dark pink in presence of blood
Tetramethylbenzidine (TMB)
Blood sample is lifted on a moisten cotton tip and applied to a Hemastix strip which contains TMB, if the strip turns blue-green then blood may be present
Leucomalachite green (LMG)
Substance that produces a green color when blood is present

11. Presumptive Tests that Glow
Luminol – fluoresces with presence of blood
Extremely sensitive can reveal blood that is 1 part per 10 million or less
Can expose blood on surfaces and fabrics even after being washed, cleaned or painted over
Can not detect after cleaning with bleach
Does not hinder DNA analysis
Fluorescein – fluoresces with presence of blood
Does not react with bleach
Thicker than luminol so it does not drip as much and remains on area for longer

12. Confirmatory Tests Most common: Teichmann and Takayama
Both rely on reaction between chemicals and hemoglobin
Results in the formation of crystals which can be viewed under the microscope
Work well with older stains

13. IS IT HUMAN? Use similar tests as ABO systems
An antiserum must be used
Substance that contains antibodies against a specific antigen
Specific antigen is human so a reaction tells you its human blood

14. How is antiserum created?
Injection of human antigen(human blood) into an animal and allowing it to produce sufficient antibodies against the antigen
The animals blood is then rich in antihuman antibodies making it the antiserum
When mixed with unknown blood from crime scene it will react:
If human it produces a line where they mix
If not human not reaction occurs

15. WHO’S BLOOD IS IT? ABO system is used to find blood type
Agglutination - clumping of blood, which tells you what type it is
Blood must be liquid and RBC’s intact
What if the blood is a stain/dried?
Absorption-elution process is used
A 4 step process to extract the remaining antigens

16. Absorption-elution Process
The bloodstained material is treated with blood antiserums
The antibodies in the antiserum combine with the antigens
The material is washed
Removes any excess antiserum-containing antibodies
The sample undergoes elution
Elution - process that breaks down antigen-antibody bonds by heating and washes off the unneeded antibodies
The eluted antibodies then are tested against known blood antigens, and their reactions are observed
Antigens and antibodies react which reveal which antigens are present in the original unknown sample

17. Narrowing it down further!
Blood Type
Population % with Blood Type O
43% A B
12% AB 3%
Use of PGM
An enzyme that appears in many different forms
10 common forms
Can be used to narrow a suspect down from more than just blood type

18. Other Bodily Fluids Semen, saliva, and vaginal fluid
Sexual assaults commonly leave these types of evidence
Can be found on ground, clothing, victim’s body or even a envelope or stamp
These fluids glow in UV light
Must be careful in collection because putrefaction can occur

19. Semen A dead victim will be searched for evidence
A live victim will undergo a rap exam at the hospital done through the use of a rape kit
Presumptive and Confirmatory tests are done

20. Presumptive Tests Semen contains high levels of AP called SAP
Acid phosphatase enzymes (AP)
Class of proteins that are common in nature and are found in many animals and plants
Semen contains high levels of AP called SAP
If SAP is present tells us that semen is present
Unfortunately vaginal fluid, certain plants – watermelon, cauliflower, some fungi, and contraceptive creams can cause a false positive
Also test for spermine and choline
Positive when crystals form when exposed to chemicals

21. Confirmatory Tests Microscopic exam Prostate-specific antigen (PSA)
If spermatozoa are present it’s semen
Can be intact or fragments
Prostate-specific antigen (PSA)
A highly concentrated antigen found in semen
If no sperm are present then test for PSA
Use an antigen-antibody reaction – quick and easy
Vasectomy
eliminates sperm release but does not effect PSA because PSA is made in the prostate!
So there is still evidence available!!

22. Saliva
This test looks for presence of amylase the enzyme present in saliva
Its not confirmatory but can be found on many surfaces even a stamp or envelope
Sometimes epithelial cells are present in saliva and can be tested for DNA analysis

23. Vaginal Fluid
Difficult to detect but can be used when semen is not available or a weapon is in question
Tests look for presence of glycogen containing epithelial cells found only in the vaginal canal
Periodic Acid-Schiff (PAS)
Chemical that when in contact with glycogen containing cells turns magenta color
Problems
Glycogen containing cells are only present in mature women who are of childbearing age
Not all cells contain glycogen