Body Fluids

Question 1

Typical fluids to be analysed

Answer 1

Blood
Semen
Salivia

Question 2

Less likely fluids to be analysed

Answer 2

Sweat
Urine (pregnancy, toxicology)
Faeces

Question 3

What do body fluids show?

Answer 3

Blood- assault, murder, injury to suspect
Semen- sexual assault
Salivia- sexual assault, bites (food and skin), mask?

Question 4

How is blood extracted from a sample?

Answer 4

Rub filter paper

Question 5

How are semen and saliva extracted from a sample?

Answer 5

Damp blotting paper

Question 6

Blood characterisation

Answer 6

Is the sample blood? Preliminary testing
Is the sample human/animal? Precipitant test
What species of animal? Anti-serum
What type of human blood? Chromosome testing (sex), testosterone (sex), clotting and crystallisation (age)

Question 7

preliminary testing for blood?

Answer 7

Not entirely specific
Prone to false reactions
Red blood cells and platelets in blood have no DNA

Question 8

What are the three preliminary tests for blood?

Answer 8

LMG
Kastle Meyer Test
Luminol

Question 9

Haemoglobin acts like a catalyst in the presence of …?

Answer 9

Hydrogen peroxide

Question 10

After filter paper rubbed over stain…

What is the process of LMG

Answer 10

Reduced leuchomalactive green added to hydrogen peroxide
Oxidised LMG
Colour change to blue/green

Question 11

Kastle Meyer test procedure?

Answer 11

Reduced phenolphthalein, added to H2O2 oxidises it if positive reaction
Colour change to red-pink

Question 12

Process of luminal preliminary testing?

Answer 12

Luminol = 3-aminophthalhydrazide
Luminol + h2o2 -> 3-aminophthalate
Light producing reaction- chemiluminescence

So spray luminal and h2o2 on region

Question 13

Why is luminol useful?

Answer 13

Shows hidden crime scene- might not have seen blood
Luminol helps find trace evidence- Locard’s principle
Blood will show even if someone has mopped up
Can lead to more evidence

Question 14

What is the problem with luminol?

Answer 14

It can destroy other evidence like finger prints and footprints
Bleach and saliva can provide a false positive

Question 15

What are the advantages for finding semen?

Answer 15

Semen can stay up till 5 days

Large amounts of DNA

Question 16

What is the first thing to do when testing for semen?

Answer 16

Dampen blotting paper and apply it to stain area

Question 17

Microscopy of semen

Answer 17

Test with staining agent

Spermatozoa

Question 18

What does acid phosphatase do in the presence of semen?

Answer 18

Produces a purple colour
Degree of colour proportional to quantity of enzyme

But also small quantity is present in vaginal fluid

Question 19

What is p30

Answer 19

Prostate specific antigen
Semen specific
And male urine

Question 20

Disadvantages to testing semen?

Answer 20

Some seminal fluid can be sterile- no Sperm

Question 21

Preliminary testing for saliva

Answer 21

Dampen blotting paper and apply to stain area
Test with iodine
Iodine turns blue black in presence of starch
Salivary amylase breaks down starch- so no colour change should occur if saliva present

Question 22

An advantage to finding saliva?

Answer 22

Saliva may contain bacterial or check cells- can look for DNA

Question 23

What does blood pattern analysis do?

Answer 23

Examines shapes, distribution and location of blood stains to interpret the events that gave rise to the origin

Question 24

How can blood analysis give information on the sequence of events?

Answer 24

You can sometimes tell if there has been struggle and the location and position of the victim

Question 25

How can blood stain analysis provide evidence to corroborate or refute statements made by those involved?

Answer 25

Stain patterns on suspects clothing and on victim/at scene

Question 26

What are the three types of blood patterns?

Answer 26

Passive Transfer Projected/Active

Question 27

What are passive patterns?

Answer 27

``` Due to gravity Drips/drops of blood Pools Clots Shape of these are affected by target surface texture- smooth/rough ```

Question 28

What are transfer patterns?

Answer 28

``` Wet bloody surface in contact with another surface produces a pattern Contact Smear Wipe Smudge ```

Question 29

What is projected blood?

Answer 29

Arterial spurt/gush- blood exiting at big pressure Cast off stains- comes from weapon (e.g. Pattern in arch- bringing back hammer) Impact- low, medium, high velocity e.g. Bullet spray Can tell point of convergence- point of impact, where victim may have been lying, follow angles of blood patterns

Question 30

The case of Billie-Joe Jenkins

Answer 30

Step father accused of murdering her He said he found her and helped 158 tiny drops of blood on his clothes- impact splatter Stabbed with tent peg But under debate has if he had lifted the body, there could have been an impact in pressure and then a fine spray- pulmonary interstitial emphysema

Question 31

What is the importance of blood grouping?

Answer 31

Large samples can be eliminated by quick inexpensive screening Used to eliminate large numbers of people

Question 32

What are the immunological biological markers? | Antigens present on blood cells

Answer 32

``` ABO Rhesus MNS Kell Duffy Kim ```

Question 33

What are the immunological systems?

Answer 33

Protein variants Groups Elimination

Question 34

What are the protein biological markers?

Answer 34

ACE ACP Haemoglobin PGM

Question 35

What antigens and antibodies are present in people with blood type A

Answer 35

A Antigens | Anti-B antibodies