Bodily fluids

Question 1

What information can bodily fluids found inside the body provide?

Answer 1

Can provide information on how an individual died

Question 2

What information can bodily fluids found at a crime scene provide?

Answer 2

-Can reconstruct story of what happened
-Can identify victim/suspect

Question 3

What does the Presence of diatoms indicate?

Answer 3

Death by drowning

Question 4

How can stomach content analysis provide information?

Answer 4

Can detect poisons or drugs

Question 5

What is the most effective way to detect bodily fluids?

Answer 5

Using different light sources

Question 6

What is ALS?

Answer 6

Alternative light source

Question 7

What must be done after bodily fluids have been detected at the crime scene?

Answer 7

Presumptive tests in the lab or at the scene

Question 8

What do presumptive tests identify?

Answer 8

Potential source

Question 9

What do confirmatory tests provide?

Answer 9

Conclusively identifies the type of biological material

Question 10

What is done following a confirmatory test?

Answer 10

Downstream analysis

Question 11

What is downstream analysis?

Answer 11

Individualises DNA

Question 12

What must lab tests be to preserve the DNA?

Answer 12

Non destructive

Question 13

How do tests vary?

Answer 13

By type of fluid

Question 14

What sensitive techniques are used to collect fluids at the scene?

Answer 14

Swabs
Tapes
Cuttings

Question 15

How can blood be used for forensic reconstruction?

Answer 15

Can identify:
-Who was involved?
-What happened?
-When did it happen?

Question 16

What does blood consists of?

Answer 16

55% plasma: Water, proteins, enzymes etc.
45 cells: RBC, WBC, platelets

Question 17

What are erythrocytes?

Answer 17

RBCs:
-Contain haemoglobin to carry O2
-Flexible shape for travel
-Antigens on surface

Question 18

What are leucocytes?

Answer 18

-Contain nuclei = DNA
-Protects against disease

Question 19

What are the different types of white blood cell?

Answer 19

Granulocytes
Lymphocytes
Monoytes

Question 20

What are thrombocytes?

Answer 20

Irregularly shaped and colourless
Forms clots
Affects blood fluidity

Question 21

What is blood type classification dependant on?

Answer 21

Presence of antibodies and antigenic substances

Question 22

What is the ABO system?

Answer 22

-Presence of either A or B antigens on RBSs determines blood type
-4 groups: A, B, AB, O

Question 23

What is the rhesus (Rh) system?

Answer 23

-RhD antigen most important and immunogenic
-present = RH+

Question 24

What is the forensic significance of red blood cells?

Answer 24

Identifies blood group antigens

Question 25

What is the forensic significance of white blood cells?

Answer 25

Contains nuclei for DNA analysis

Question 26

What is the forensic significance of plasma?

Answer 26

Drug/alcohol screening Species testing

Question 27

What information can blood pattern analysis provide?

Answer 27

What happened? Order of events?

Question 28

What are active blood stains?

Answer 28

Blood travels by a force other than gravity

Question 29

What causes a blood spatter?

Answer 29

Impact of the weapon to the body

Question 30

What causes gushes or spurts of blood?

Answer 30

Projection from a punctured artery

Question 31

What causes cast off stains?

Answer 31

Secondary objects, i.e. the weapon

Question 32

What is a passive bloodstain?

Answer 32

Blood forms solely under the influence of gravity

Question 33

How can body position affect the bloodstain?

Answer 33

Affects the blood distribution

Question 34

What information can a passive blood stain provide?

Answer 34

-Time since bloodshed -Angle of impact

Question 35

What is a transfer bloodstain?

Answer 35

Blood deposit = direct contact with contaminated objects

Question 36

What does a transfer bloodstain indicate?

Answer 36

Repeated contacts

Question 37

What are presumptive tests?

Answer 37

Test unknown stains at crime scene or in the lab

Question 38

What are examples of presumptive tests?

Answer 38

-Screening techniques -Catalytic techniques

Question 39

What are examples of screening techniques?

Answer 39

-ALS -Chemiluminescence

Question 40

What are screening techniques used for?

Answer 40

Non-visible traces

Question 41

What are the benefits of screening techniques?

Answer 41

-Rapid -Non-destructive

Question 42

How are catalytic tests performed?

Answer 42

Add reagents to a presumed sample of blood Colour change = a positive result

Question 43

What are examples of catalytic tests?

Answer 43

-Kastle-meyer test -LMG test

Question 44

What causes a colour change in catalytic tests?

Answer 44

Haemoglobin catalyses the oxidation of reagents

Question 45

What is a positive colour change for the kastle-meyer test?

Answer 45

Pink

Question 46

What catalytic test is recommended?

Answer 46

luminol - preserves DNA most effectively

Question 47

What does a confirmatory test for blood involve?

Answer 47

-Crystal tests expose blood stains to different acids -Spectroscopy -Microscopic assesments of RBCs and WBCs

Question 48

What are serological tests?

Answer 48

Precipitin tests used to identify human proteins

Question 49

What are serological tests used for?

Answer 49

Associates or excludes individuals

Question 50

What information can forensic analysis of saliva provide?

Answer 50

-DNA of accused -Detect drugs and alcohol -Poisoning cases -Hormone levels -Species identification

Question 51

What is the role of saliva?

Answer 51

A digestive aid produced passively to break down food starches

Question 52

What does saliva consist of?

Answer 52

99% water 1% electrolytes, proteins, enzymes, immunoglobins

Question 53

How can saliva be analysed?

Answer 53

ALS screening Enzymatic methods *No confirmatory tests

Question 54

What is enzymatic analysis of saliva?

Answer 54

-Presence of a-amylase enzyme confirms saliva

Question 55

How is enzymatic analysis conducted?

Answer 55

-Sample stain added to soluble starch solution -Iodine added as a reagent -No reaction indicates starch has been digested and enzyme is present

Question 56

What are drawbacks of enzymatic analysis of saliva?

Answer 56

-Non specific for human saliva -High false +ve rate

Question 57

Why is speed important when testing for semen?

Answer 57

Detectable for a short period of time

Question 58

What are the components of semen?

Answer 58

Complex fluid and cellular mixture

Question 59

What does the cellular mixture of semen consist of?

Answer 59

Spermatozoa cells containing genetic material

Question 60

What does the complex fluid of semen consist of?

Answer 60

Provides a protective, nutrient rich environment for sperm cells

Question 61

What is the function of semen?

Answer 61

-Sexual production

Question 62

What are the presumptive tests for semen?

Answer 62

-ALS -Test for seminal acid phosphatase -Test for prostate specific antigens

Question 63

What are confirmatory tests for semen?

Answer 63

Microscopic ID of sperm cells -Stained to visualise RS-ID semen strip test

Question 64

What does vaginal secretion consist of?

Answer 64

-Liquid by-product of metabolism -Nitrogen rich -Urea -Uric acid -95% water

Question 65

What tests detect ammonia in vaginal secretions?

Answer 65

-Nesslers -DMAC reagent

Question 66

How is sweat useful in forensics?

Answer 66

DNA evidence can be extracted

Question 67

What is the function of sweat?

Answer 67

-Thermoregulation

Question 68

What is sweat composed of?

Answer 68

-Lactic acid -Urea -Creatinine -Na, K, Ca, Mg

Question 69

What are the tests for sweat?

Answer 69

-SEM-EDX -G-81 monoclonal antibody -Metabolite biometrics

Question 70

What information can sweat analysis provide?

Answer 70

-Drug use -Alcohol consumption

Question 71

Why is the source of bodily fluid evidence important?

Answer 71

Context of the case

Question 72

What does downstream DNA analysis of body fluids allow?

Answer 72

Enables robust identification