1. Created by C. Ippolito January 2008
Forensic Serology
Objectives:
Identify and describe the components of human blood
List the A-B-O antigens and antibodies found in the blood for each of the four blood types: A, B, AB, and O.
Explain why agglutination occurs.
Explain how whole blood is typed.
Describe tests used to characterize a stain as blood.
Explain the significance of the precipitin test to forensic serology.
Explain the differences between monoclonal and polyclonal antibodies.
Define chromosome and gene.
How is the Punnet square used to determine the genotypes and phenotypes of offspring?
List the laboratory tests necessary to characterize seminal stains.
Explain how suspect stains are to be properly preserved for laboratory examination.
Describe the collection of physical evidence related to a rape investigation.
11/29/2018
Created by C. Ippolito January 2008

2. Created by C. Ippolito January 2008
Blood
complex mixture of cells and fluid
Formed Elements
living component
cells suspended in the liquid
Plasma
nonliving fluid matrix of unclotted blood
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Created by C. Ippolito January 2008

3. Created by C. Ippolito January 2008
Plasma
55% of whole blood
90% water
10% dissolved components
nutrients
sugars, lipids (fats), amino acids
gases
CO2 (bicarbonate ion HCO3-)
salts
ionic compounds containing (Na+, K+, Mg2+, Cl-)
hormones
plasma proteins
albumen – maintains osmotic pressure, pH buffering
globulins - antibodies – protective proteins of immune response
fibrinogen – protein that contributes to blood clotting mechanism
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Created by C. Ippolito January 2008

4. Created by C. Ippolito January 2008
Formed Elements
45% of whole blood
Three main blood cell types
Erythrocytes (RBC)
transport O2
Leukocytes (WBC)
disease defense
Thrombocytes (platelets)
clotting mechanism
cell pieces
initiate clotting
11/29/2018
Created by C. Ippolito January 2008

5. Created by C. Ippolito January 2008
Erythrocytes
most numerous blood cells
anucleate – no nucleus
hemoglobin (Hb)
iron containing protein
transports O2
biconcave disk
increases surface area
membrane antigens
determine blood types
Anemia
lack of RBC
Polycythemia
excess RBC
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Created by C. Ippolito January 2008

6. Created by C. Ippolito January 2008
Leukocytes
less numerous blood cells
defense against
bacteria, viruses, parasites, tumor cells
Leukocytosis
high WBC count
indicative of infection
Leukopenia
low WBC count
corticosteroid use, certain drugs, anticancer agents
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Created by C. Ippolito January 2008

7. Created by C. Ippolito January 2008
Types of Leukocytes
Neutrophils
phagocytes – “eating cells”
attack in acute (short-term) infections
Eosinophils
attack parasitic worms
numerous during allergies
Basophils
release histamine
vasodilator releases plasma and WBC at infection site
Lymphocytes
B-cells – release antibodies
T-cells – attack viruses and tumors, activate B-cells
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Created by C. Ippolito January 2008

8. Created by C. Ippolito January 2008
Human Blood Groups
RBC antigens
antigen
identifying protein that is genetically determined
recognized by a “body” as being foreign
antibody
protein released by B-cells
“match” antigens’ shape
minimum of 2 active sites (bivalent)
Agglutination
antibodies attach to RBC antigens
RBC interconnect through antibodies
RBC clump together clogging BV
Serum
plasma with antibodies
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Created by C. Ippolito January 2008

9. Created by C. Ippolito January 2008
RBC Agglutination
RBC membrane antigen
Antibody matches and attaches to multiple RBCs
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Created by C. Ippolito January 2008

10. Created by C. Ippolito January 2008
ABO Blood Typing
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Created by C. Ippolito January 2008

11. Created by C. Ippolito January 2008
Type AB Blood
RBC has both antigens A and B
reacts with anti-A serum
reacts with anti-B serum
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Created by C. Ippolito January 2008

12. Created by C. Ippolito January 2008
Type A Blood
RBC has only antigen A
reacts with anti-A serum only
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Created by C. Ippolito January 2008

13. Created by C. Ippolito January 2008
Type B Blood
RBC has only antigen A
reacts with anti-B serum only
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Created by C. Ippolito January 2008

14. Created by C. Ippolito January 2008
Type O Blood
RBC has no antigen
no reaction with anti-A serum
no reaction with anti-B serum
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Created by C. Ippolito January 2008

15. Blood Type Distribution
In the US a “typical” ABO distribution is as follows:
43% type O
42% type A
12% type B
3% type AB
ABO Blood Type distributions
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Created by C. Ippolito January 2008

16. Created by C. Ippolito January 2008
Immunoassay
Using antibody-antigen reactions to identify substances
original pregnancy tests (clotting to HCG)
use rabbits to make antibodies to react with drugs
antibodies (sera) then used in urinalysis
opiates, cannabinoids, cocaine, amphetamines, phencyclidine, barbiturates, methadone can be identified,
presumptive testing, results must be confirmed by additional tests
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Created by C. Ippolito January 2008

17. Radioimmunoassay (RIA)
uses drugs labeled with radioactive tags
can react with substances chemically similar to target substance
also needs confirmation
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Created by C. Ippolito January 2008

18. Created by C. Ippolito January 2008
EMIT
Enzyme-Multiplied Immunoassay Technique
add antibodies to urine for particular drug
add chemically labeled version of presumed drug
competition between labeled and unlabeled
amount of labeled drug left in test related to amount of original drug in sample
labeled drug left over means original drug combined with antibodies and was removed
used to test for THC (tetrahydrocannabinol) and it metabolites such as THC-9-carboxylic acid
shows marijuana use but can yield positive results for up to 10 days after last use
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Created by C. Ippolito January 2008

19. Polyclonal and Monoclonal Antibodies
Polyclonal antibodies
multiple antibodies produced to attack many different parts of a single antigen
preferable in immune response against a disease organism
Monoclonal antibodies
single antibody produced to attack a specific part of a specific antigen
preferable in an “assay” test to identify one particular substance
hybridoma cells
mouse spleen cells and blood cancer cells combine producing a single antibody
11/29/2018
Created by C. Ippolito January 2008

20. Forensic Characterization of Blood Stains
Three questions must be answered:
Is it blood?
Color Tests
Luminol Test
Microcrystalline Test
Is it human blood?
Precipitin Test
Gel Diffusion Test
Can it be associated with a particular person?
ABO typing (rarely done)
DNA profiling
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Created by C. Ippolito January 2008

21. Created by C. Ippolito January 2008
Color Tests
Hemoglobin – acts like peroxidase
enzyme accelerates oxidation in presence of hydrogen peroxide causing a color change
enzyme also found in potatoes and horse radish
pink color indicates presence of hemoglobin
Benzidine Test
discontinued as a carcinogen
Kastle-Meyer Test
uses phenolphthalein
Hemastix
dipstick test for blood in urine
used as presumptive blood test when moistened with distilled water
turns green when in contact with blood
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Created by C. Ippolito January 2008

22. Created by C. Ippolito January 2008
Luminol Test
Luminol
luminol + hydrogen peroxide  3-aminophthalate
luminescence rxn
chemical produces blue light
does not affect subsequent DNA testing
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Created by C. Ippolito January 2008

23. Microcrystalline Tests
addition of chemicals causes hemoglobin to crystallize
susceptible to contaminants giving false positives
Takayama Test
Teichmann Test
Wagenhaar test
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Created by C. Ippolito January 2008

24. Created by C. Ippolito January 2008
Precipitin Tests
Human antiserum
derived from animal antibodies produced in response to exposure to human blood
rabbits, cat, dogs, deer used as sources
reaction of antigen-antibody forms cloudy ring where they meet in capillary/test tube
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Created by C. Ippolito January 2008

25. Created by C. Ippolito January 2008
Gel Diffusion Test
antigen-antibody reaction
coagulate when meet
very sensitive
works with dried blood stains after 15 years
can be diluted to 1/256 and still react
11/29/2018
Created by C. Ippolito January 2008