1. Forensic Serology Chapter 10

2. Karl Landsteiner
In 1901 he discovered that all humans do not have the same blood type
He discovered the A-B-O blood group system
This saved millions of lives by preventing mismatched blood transfusions
Other researchers were able to discover the Rh factor because of his research
29 years later, they gave Karl a Nobel Prize

3. Other Blood Factors
The ABO proteins and Rh factor proteins are not the only proteins on the surface of blood cells
There are more than a 100 different surface blood factors
But the ABO factors are most important for matching a donor to a recipient

4. Blood and Forensics
No 2 individuals (except identical twins) can share all the 100+ blood factors
So forensic scientists used this tool to link blood from a crime scene to an individual
After 1990 however, DNA fingerprinting has been used instead of blood typing to identify blood stains and other biological evidence.

5. What is Blood?
Various cell types found in a liquid matrix called plasma
Erythrocytes (RBCs)
Transport O2, CO2
Stay within blood vessels
Leukocytes (WBCs)
Fight infection (immune system)
Can move from blood vessels into tissues
Platelets (Cell fragments)
Help with clotting

6. White Blood Cell
Platelets
Red Blood Cells

7. Characteristics of Red Blood Cells
Red blood cells (erythrocytes) are biconcave disks that contain oxygen-carrying hemoglobin.
Red blood cells discard their nuclei, mitochondria and most organelles during development and so cannot reproduce or produce proteins.
In addition to 100s of cell surface proteins, their cell surfaces have a special class of blood factor proteins called Antigens.
There are at least 15 different antigens, but the most important are the ABO and Rh antigens

8. Role of RBCs Transport inhaled O2 from lungs to all body cells
Remove CO2 from all body cells and take it back to lungs for exhalation
When oxygen combines with hemoglobin bright red oxyhemoglobin results.
Deoxygenated blood or blood containing CO2 (deoxyhemoglbin) is darker.
RBCs are destroyed after about 120 days

9. Summary of Functions of WBCs
Leukocytes can squeeze between cells lining walls of blood vessels by diapedesis and attack bacteria and debris.
Neutrophils and monocytes are phagocytic, with monocytes engulfing the larger particles.
Eosinophils moderate allergic reactions as well as defend against parasitic infections.
Basophils migrate to damaged tissues and release histamine to promote inflammation and heparin to inhibit blood clotting.
Lymphocytes are the major players in specific immune reactions and some produce antibodies (T cells and B cells)

10. Blood Platelets Blood platelets are fragments of cells
Platelets help repair damaged blood vessels by adhering to their broken edges.
Thrombopenia, or low platelet counts increase bleeding risks
Thrombocytosis or high platelet count may lead to thrombosis (clotting, bruising, strokes, heart attacks).

11. Blood Plasma
Plasma is the clear, straw-colored fluid portion of the blood.
Plasma is mostly water, with a mixture of, amino acids, proteins, carbohydrates, lipids, vitamins, hormones, electrolytes, and cellular wastes

12. Hematocrit A blood hematocrit is normally 45% cells and 55% plasma.
Hematocrit means the percentage of red blood cells in blood
A blood hematocrit is normally 45% cells and 55% plasma.

13. ABO Blood Group
Type A blood has A antigens on red blood cells and anti-B antibodies in the plasma.
Type B blood has B antigens on red blood cells and anti-A antibodies in the plasma.
Type AB blood has both A and B antigens, but no antibodies in the plasma.
Type O blood has neither antigen, but both types of antibodies in the plasma.
Adverse transfusion reactions are avoided by preventing the mixing of blood that contains matching antigens and antibodies.
Adverse reactions are due to the agglutination of red blood cells.

15. Rh Blood Group The Rh factor was named after the rhesus monkey.
If the Rh factor surface protein is present on red blood cells, the blood is Rh positive; otherwise it is Rh negative.
There are no corresponding antibodies in the plasma unless a person with Rh-negative blood is transfused with Rh-positive blood; the person will only then develop antibodies for the Rh factor.

16. Blood Groups and Transfusions Antigens and Antibodies
Clumping of red blood cells following transfusion is called agglutination.
Agglutination is due to the interaction of proteins on the surfaces of red blood cells (antigens) with certain antibodies carried in the plasma.
Only a few of the antigens on red blood cells produce transfusion reactions.
These include the ABO group and Rh group.

18. Antibody: a protein that destroys or inactivates a specific protein antigen. Antibodies are found in the blood serum
Antibodies are very SPECIFIC to an antigen. They are designed by the immune system to fit an antigen.
Antiserum: blood serum in which there are specific antibodies
Agglutination: the clumping together of red blood cells by the action of an antibody

19. Antibodies or Agglutinins
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

20. Relative Frequency of Blood Types in Human Populations

21. DRUG - DETECTION
Hypothesis: Since foreign substances in blood are identified and then isolated by the immune system, it should be able to detect the presence of drugs and other chemicals. This hypothesis is incorrect. The immune system only creates antibodies and launches attacks against foreign proteins (either free proteins or ones bound to cells) and not against other chemical compounds.

22. We can fool the immune system
The drug can be attached to a carrier molecule that is a protein
This drug-protein combo can be injected into an animal such as a rabbit or rat (no human volunteers)
The animal’s immune system will create antibodies that are specific to the shape of this drug-protein combo molecule
We can isolate these antibodies from the animal’s blood serum
And use these antibodies to detect the presence of the drug in human blood or urine

23. Now how does a criminalist use these monoclonal antibodies?
To detect drug presence in blood, urine, etc.
A.K.A. EMIT assays (bio jargon for test)
EMIT stands for Enzyme-multiplied Immunoassay Technique
EMIT is most often used to test for marijuana (THC) metabolites in urine.
One of the primary THC metabolites is THC-9-carboxylic acid

24. How EMIT works
Let’s suppose you’re checking someone’s urine for the presence of THC-9-carboxylic acid (from THC or Marijuana.)
Take urine sample to be tested
Add monoclonal antibodies for THC-9-carboxylic acid to the urine
The antibodies will immediately bind to any THC-9-carboxylic acid molecules present in the urine
Then add enzyme-labeled THC-9-carboxylic acid molecules to the urine
Any antibodies that did not bind to THC-9-carboxylic acid prior to this step (extra antibody molecules), will bind to the enzyme-labeled THC-9-carboxylic acid
One can now measure the amount of unbound or unused enzyme-labeled THC-9-carboxylic acid to get a value of THC originally present in the urine.

25. Questions for a Criminalist
Is it blood?
Is it human blood?
If it is human, can it be linked to a suspect / victim and how closely?

26. Color tests to identify human blood
The Benzidine color test was used for years to identify human blood
But benzidine was identified as a carcinogen, so nowadays the phenolphthalein test is performed instead.
The phenolphthalein test is also known as the Kastle-Meyer color test
Both, the benzidine and the Kastle-Meyer test look for the presence of hemoglobin in the sample.

27. The Kastle-Meyer Test
When blood, phenolphthalein and hydrogen peroxide are mixed, the hemoglobin in the blood will cause the normally colorless phenolphthalein to a bright pink color
This test can yield some false positives
Certain vegetable matter can produce the bright pink positive (such as potatoes)

28. Death By Potato?
Although the Kastle-Meyer test can give a false positive in the presence of certain plant matter, it is unlikely that this plant matter would be present at a crime scene and be mistaken for blood.

29. Other blood detection tests
Doctors use Hemastix© strips to detect blood in urine
But these strips can be used at a crime scene to detect fresh or dried blood.
One simply moistens them with distilled water and wipes the bloodstain
A color change to green is a positive
indicator of blood

30. Luminol
Luminol is a chemical that exhibits chemiluminescence, with a striking blue glow, when mixed with an appropriate oxidizing agent. It is a white to slightly yellow crystalline solid that is soluble in water and most polar organic solvents.
Usually, a solution of hydrogen peroxide (H2O2) and a hydroxide in water is used as the activator.
In the presence of a catalyst such as an iron compound, the hydrogen peroxide is decomposed to form oxygen and water:

31. What do you see with luminol?
It glows a bright blue in the dark, when it comes in contact with blood

32. Advantages of using Luminol
Allows one to detect stains that would not be ordinarily be visible
Extremely sensitive - can use it in very dilute concentrations
This allows the CSI to spray large areas with it
It does not interfere with DNA, so a CSI can collect samples for DNA analysis even after it was sprayed with luminol.

33. Bloody Footprints that were wiped

34. Drawbacks
Luminol glows even in the presence of certain other fluids – semen, feces, bleach, tonic water, etc.
Luminol glows in the presence of certain vegetable matter - Mr. Potato head strikes again!

35. Thanks to Quinine

36. Crystal Tests Less sensitive than color tests
They involve the crystallization of certain components of blood when certain chemicals are added
Takayama test and Teichman test
Not used as much by CSI

37. So we know it’s blood – but is it human?
The Precipitin Test
Rabbits injected with human blood
They make antibodies in their serum
They are bled and the serum recovered
The serum is called human antiserum, because it will react to human antigens
It will cause coagulation when mixed with human blood

38. Precipitin Test
(Human blood)
(Human antiserum made in rabbits)

39. Gel Diffusion Test
Antigen (blood) and antibodies (human antiserum from rabbits) are placed in separate wells in a gel.
They are forced to move towards each other.
If they bind to each other, they form a single line of precipitate in between the wells
This is a positive for human blood

40. DNA TEST DNA testing is the ultimate
It has made most other tests for determining if the blood is human, obsolete

41. Analyzing Bloodstain Patterns
Surface Texture
The harder and less porous the a surface, the less spatter results
Direction of travel
The pointed end of a bloodstain always faces the direction of travel
Impact angle
If the strike angle is 90deg then the stain is circular. As the strike angle increases, the stain becomes more and more elongated
Origin of blood spatter
If you draw straight lines through the long axis of several blood stains, the point where the lines converge is the origin of the blood spatter

45. Types of Blood Stain Patterns
Passive
Projected
Transfer

46. Passive Bloodstains
Passive stains are drops created or formed by the force of gravity acting alone.
This category can be
further subdivided to
include:
Drops
Drips
Pools

47. Passive drops on various surfaces
Blood droplets that strike a hard smooth surface, like a piece of glass, will have little or no distortion around the edge.
Blood droplets that strike a rough surface have a slightly different appearance. They tend to be distorted, scalloped or spined at the edges.

48. Passive: Dripped Blood
Patterns created by a volume of blood, from same source to target distance (repeated drops onto same spot.)

49. Projected Bloodstains
Projected bloodstains are created when an exposed blood source is subjected to an action or force, greater than the force of gravity. (Internally or Externally produced)
The size, shape, and number of resulting stains will depend, primarily, on the amount of force utilized to strike the blood source.
This category can be further subdivided to include:
Arterial Gush or spurt
Cast-off stains
Impact spatter (medium or high velocity)

50. Arterial gush or spurt
Bloodstain pattern(s) resulting from blood exiting the body under pressure from a breached artery.

51. Cast-off Stains
Blood released or thrown from a blood-bearing object in motion (Knives, bludgeons)

52. Projected blood through a syringe

53. Impact Spatter
Blood stain patterns created when a blood source receives a blow or force resulting in the random dispersion of smaller drops of blood.
This category can be further subdivided into;
Low Velocity
Medium Velocity
High Velocity

54. Low Velocity Impact Spatter
Gravitational pull up to 5 feet/sec.
Relatively large stains 4mm in size and greater

55. Medium Velocity Impact Spatter
Force of 5 to 25 feet/sec.
Preponderant stain size 1 to 4mm in size

56. High Velocity Impact Spatter
Force of 100 feet/sec. and greater Preponderant stain size 1mm in size and smaller Mist like appearance

57. Transfer Bloodstains
A transfer bloodstain is created when a wet, bloody surface comes in contact with a secondary surface.
A recognizable image of all or a portion of the original surface may be observed in the pattern, as in the case of a bloody hand or footwear.