Chapter 15 (Forensic Serology)

For blood, the fluid portion is and what does it contain?

Plasma

Contains: Red, white and platelets.

Transport oxygen to tissue, and transport CO2 from tissues to lung where its exhaled.

Red blood cells

On the surface of the RBC are?

Antigens (markers or “flags” )

Give the cell a class characteristic (blood type ABO).

Antigens (markers or “flags” )

Used to describe a broad scope of laboratory tests that use specific antigen and serum antibody reactions.

Serology

For routine blood typing ____________ is used.

Anti-A and anti-B serum

______________ are used/seen to determine blood group.

Agglutination reactions

What is the Typical distribution of blood types?
O
A
B
AB

43%=O

42%=A

12%=B

3%=AB

_________________ are used by screening labs.

Immunoassay techniques

Uses the antigen-antibody reaction to screen blood or urine for the detection of drugs.

Only presumptive in nature

Need confirmatory tests

Immunoassay techniques

What are the types of blood tests?

Color test

Luminol and Bluestar

Microcrystal test

Precipitin test

Gel Diffusion

Criminalist must answer the following questions when examining dried blood:

Is it blood?

What species did it come from?

If human can we associate it with a particular individual?

Describe the color test for blood

Test: Is it blood?

Use phenolphthalein = deep pink

__________ and ___________ both are luminescent tests for blood

Luminol and Bluestar

What are the types of Microcrystal test?

Takayama and Teichmann tests

What test is used to determine if human or animal blood?

Precipitin test

What test is used to determine if human or animal blood?

Gel Diffusion

What is an advantage when using gel diffusion?

Very sensitive and can be used on blood many years old.

• Egg contains the X chromosome
• Sperm contains the X or the Y chromosome, therefore the father dictates
the sex of the baby.
• XX = female
• XY = male

DNA to genes to Chromosomes (T/F)

True

Nucleated cells contain ___ chromosomes

46 chromosomes (23 pairs)

RBC do not contain DNA. (T/F)

True

Sperm contains ___ single chromosomes

Egg contains ___ single chromosomes (unpaired).

Sperm contains 23 single chromosomes

Egg contains 23 single chromosomes (unpaired).

When together you get 23 paired chromosomes (zygote = 23 paired chromosomes).

What are the two steps when finding semen?

Stain must be located

Test for identity.

To locate and see if the stain is semen what test is used?

Acid Phosphatase test

An enzyme found in seminal fluid.

Acid Phosphatase

When an area is suspected of containing seminal fluid what are the steps that must be done?

1. A moistened cloth or paper is rubbed lightly over the stain/area

2. Sodium alpha naphthylphosphate (wait 30 seconds)

3. Fast Blue B reagent is dropped onto the paper

4. Purple color indicates (+) for acid phosphatase (within 10-30 seconds)

Best way to identify is to see the presence of spermatozoa is?

Microscopic examination

How would you use the microscope when doing the examination of Semen?

Need a microscope 400x

Need staining reagent.

Can use immunology-fluorescence staining

What if no spermatozoa is present, how do you unequivocally prove the presence of semen?

The presence of p30 (protein)

PSA (Prostate Specific Antigen)

VERY important for Nurses that want to specialize in SANE (sexual assault nurse examiner) protocols.

Collection and Preservation of rape Evidence

Rape may involve the presence of ______________, which is evidence that sexual intercourse has taken place.

Seminal constituents

But even if no semen is found it does not mean that rape did not occur, what are ways to notice?

Physical injuries (Bruises or bleeding) tend to confirm that a violent assault did take place.

Forceful physical contact between victim and assailant may result in transfer of physical evidence such as?

Blood

Semen

Hairs

Fibers.

These pieces of evidence will help link the sexual crime

For collection and handling of rape Evidence what should you do?

All outer and undergarments should be packages separately in paper bags.

Use a clean bedsheet and place a clean white paper sheet over it.

Victim removes shoes and steps into the white paper

(All items are collected letting any trace evidence land on the paper for examination, along with the clothing recovered)

Bedsheets or item used in assault needs to be collected carefully as to not be contaminated by person collecting the item. (T/F)

True

Items that need to be collected: Victim

Pubic combings

Pubic standards – 25 hairs from pubic area

External genital dry-skin area – 1 dry 1 moist swab

Vaginal swab and smear – swab area and let dry, do same but smear on slide (let dry and pack).

Cervix swab – swab let dry and pack

Rectal swab and smear – 1 dry after swabbing, one smear on slide let dry.

Oral swab and smear – 2 to buccal area and gum line, smear one on slide, pack both when dry.

Swabs of body areas – swab area and pack. (moist and dry swab)

Head hairs – 25 total from different locations.

Blood sample - 20ml collected, for tox screen.

Collect buccal swab for DNA typing – see ch 16.

Fingernail scraping – scrape undersurface of the nails, onto paper, one per hand.

All clothing – separate

Urine specimen – 30 ml , tox test or GHB, 1,4 BD, Rohypnol analysis.

What must be collected from Suspect?

All clothing worn during assault

Pubic hair combings

Pulled hair from head and pubic region

Penile swab

Buccal swab, for DNA typing

Biological material from the victim may still be on inside front surface of assailant’s underwear.

When analyzing seminal constituents, what can it help you establish?

A time of attack/assault

Living/motile sperm last how long in the birth canal?

4-6 hours

Analysis must be done immediately after swabbing for seminal constituents (T/F)

True

Nonmotile sperm can be found how many days after assault?

3 days

PSA can last 72 hrs (T/F)

True