1. Forensic Serology
Chapter 8

2. Blood Components Plasma--fluid part of blood unclotted blood
Erythrocytes—hold hemoglobin and transport oxygen
Leukocytes—immune cells
Platelets--clotting
Serum—yellow fluid that remains after clotting of blood, mostly water + dissolved substances (proteins, ions, etc)

3. Antigen and Antibodies
Blood Type A has A antigens and B antibodies
Blood Type B has B antigens and A antibodies
Blood Type AB has both A and B antigens and no antibodies
Blood Type O does not have any antigens but both A and B antibodies
Positive blood has Rh(D) antigens = Rh+
Negative blood does not have Rh(D) antigens but has D antibodies = Rh-

4. Serology Positive blood will agglutinate with Anti D serum
Negative blood will not agglutinate with Anti D serum
A blood will agglutinate with Anti A serum
B blood will agglutinate with Anti B serum
AB blood will agglutinate with both anti A and anti B serum
O blood will not agglutinate with anti A or anti B

5. Paternity Testing with Blood Type
A Blood Type—AA or AO
B Blood Type—BB or BO
O Blood Type—OO
AB Blood Type—AB
Parent gives each offspring one of two alleles

6. Immunoassay techniques
Used to detect drugs in blood and urine
Animals are injected with proteins with drug antigens—animal makes drug detecting antibodies that can be harvested
Presumptive drug testing with these cultured antibodies can be used to detect opiates, cannabinoids, cocaine, amphetamines, phencyclidine, barbituates and methodone

7. Producing Antibodies
Radioimmunoassay (RIA)—uses radioactive tags to find drugs
Enzyme-Multiplied Immunoassay Technique (EMIT)—fast and used with urine; adds antibodies to urine that bind to specific drugs
Polyclonal and Monoclonal Antibodies—animals produce many different antibodies when exposed is polyclonal; scientists need one kind of antibody (monoclonal; fused with cancer cell to make hybridoma cell

8. Blood Stain Analysis 3 Questions Is it blood? Is it human?
Can it be matched closely to a particular person?

9. Presumptive Color Testing
Benzadine color test—use has been reduced because it is a carcinogen; measures for presence of hemoglobin
Kastle-Mayer—uses phenolphthalein as an indicator, and hydrogen peroxide to cause the conversion of catalase to give pink color; will test positive with samples with catalase (animal and some plant material)

10. Luminol Presumptive blood test
Reaction with blood emits light that can be seen in darkened area
Sprayed on area, turn dark, emits blue light

11. Microcrystalline Tests
Takayama test
Teichmann tests
Add chemicals to blood that causes hemoglobin-containing crystals to form
Susceptible to contaminants and less sensitive that color tests

12. Precipitin Test
Used to determine if blood stain is human or from animal
Grow antibodies to human blood in rabbit; use antibodies to test for presence of human antigens; Human antiserum
Rabbits can be used to make antibodies against various animal bloods as well

13. Gel Diffusion
Use agar gel—antibodies and antigens come together in medium plate
Blood and human antiserum are loaded into wells
Precipitant forms if blood is human between two wells

14. Blood Spatter Important Blood Qualities to Interpret Blood Spatter
Surface texture—more spatter with softer, porous material
Direction of travel—pointed end faces direction of travel
Impact angle—right angle yields circular stain
Origin of spatter—draw lines through many spatter points; point of intersection is origin of spatter

15. Forensic Analysis of Semen
Tests for Presence of Semen
Acid Phosphatase Stain—acid phosphatase is made by the prostate gland and added to semen during ejaculation; presence can be detected by acidic sodium alpha napthylphosphate and fast blue dye or 4-methyl umbelliferyl phosphate (will fluoresce)
Microscopic examination—look for presence of sperm cells
Prostate specific antigen—polyclonal antibodies grown in rabbits used to bind to p30 protein or prostate specific antigen

16. Rape Evidence Collection
Rape Kit Collection from victims
Hair samples: head, pubic, body
Body opening swabs: vagina, anus, mouth
Blood sample
Fingernail scrapings
All clothing
Urine sample
Collected from male suspects
All clothing
Hair: head, pubic, and body
Genital swab
Blood sample
Cheek cells