Bodily Fluids

Question 1

How are bodily fluids visually identified?

Answer 1

• alternate light source i.e. torch
• stain characteristics i.e. shape, colour

Question 2

What are the cellular components of blood?

Answer 2

• RBC
• Non-granular leukocytes (WBC)
• Granular leukocytes (WBC)
• blood clotting

Question 3

What is blood made up of?

Answer 3

Plasma + cells

Question 4

What is blood plasma made up of?

Answer 4

• water
• plasma proteins
• salts
• food substances
• hormones
• enzymes
• metabolism waste products

Question 5

Describe KM/LMG

Answer 5

• detect peroxidase activity in blood
• 2 reagents; H2O2 and reduced dye (phenolph or LMG)
• colourless if -ve, pink/green if +ve

Question 6

Is KM/LMG a presumptive or confirmatory test for blood?

Answer 6

presumptive

Question 7

Describe Haemastix

Answer 7

• square sponge on end of stick with Tetramethylbenzidine
• turns blue-green with blood

Question 8

Is Haemastix a presumptive or confirmatory test for blood?

Answer 8

presumptive

Question 9

Describe luminol

Answer 9

• detects peroxidase activity in blood and glows (short-lived)
• highly sensitive, enhances blood traces

Question 10

Is luminol a presumptive or confirmatory test for blood?

Answer 10

presumptive

Question 11

What is a spot test (blood)?

Answer 11

Visible stains with blood-like appearance, rub stain with folded filter paper and KM/LMG

Question 12

What is a screening test (blood)?

Answer 12

Dark coloured items where blood is not readily visible, methodically rub sections

Question 13

What is a direct test (blood)?

Answer 13

Dilute stains, cut thread from exhibit and test directly on filter paper

Question 14

What are some false positives for blood presumptive tests?

Answer 14

Plant material, oxidising agents i.e. cleaning chemicals, animal blood, clothing dye

Question 15

Describe ABA Haematrace

Answer 15

Blood kit used to confirm presence of human blood

Question 16

Is ABA Haematrace presumptive or confirmatory for blood?

Answer 16

Confirmatory

Question 17

Describe semen

Answer 17

slightly alkaline, pre can be AP and sperm rich, seminal fluid is rich in enzymes i.e AP, hormones, fructose, etc.

Question 18

Describe sperm morphology

Answer 18

Head with acrosome, midpiece with mitochondria, tails

Question 19

Describe the AP test

Answer 19

• detects acid phosphatase in seminal fluid (forensic press test)
• a-naphthyl phosphate and brentamine fast blue
• produces purple azo dye if positive

Question 20

Is the AP test a presumptive or confirmatory test for semen?

Answer 20

presumptive

Question 21

What are some limitations of the AP test?

Answer 21

• many false positives
• AP breaks down 48hr after ejaculation

Question 22

How is excess cellular material removed from samples for better viewing?

Answer 22

• Sodium Dodecyl Sulfate (SDS): detergent that denatures membrane proteins
• Proteinase K (ProK): breaks down polypeptide chains into smaller ones

Question 23

What is the confirmatory test for semen?

Answer 23

Microscopy to reveal presence of sperm

Question 24

Describe 3 stains used in tandem with microscopy to confirm the presence of semen

Answer 24

• Florence Iodine: detects choline, forms short golden-brown crystals if +ve
• Christmas Tree: nuclear fast red stains heads red, picroindigocarmine stains tails green
• H&E: haematoxylin stains heads purple/blue, eosin stains tails pink

Question 25

What is saliva made up of?

Answer 25

Mucin, alkaline phosphate, thiocyanite ions, nitrate ions, epithelial an bacterial cells, amylase

Question 26

What is the purpose of saliva

Answer 26

Aid digestion

Question 27

Describe the Phadebas test

Answer 27

- detects alpha amylase in saliva - sprayed onto test paper, pressed into exhibit, sprayed with iodine working solution, amylase breaks down starch and blue dye is released if +ve

Question 28

What are the limitations of the Phadebas test?

Answer 28

- requires regular observation/time consuming - false negatives - not specific to salivary amylase

Question 29

Is Phadebas confirmatory or presumptive for saliva?

Answer 29

Presumptive

Question 30

What is the confirmatory test for saliva?

Answer 30

Microscopy to reveal presence of cheek buccal cells

Question 31

What is urine made of?

Answer 31

urea, creatine, dissolved salts, organic material

Question 32

Describe the Creatinine test for urine

Answer 32

- produces orange colour with picric acid in alkaline medium

Question 33

Is the creatinine test presumptive or confirmatory for urine?

Answer 33

presumptive

Question 34

Is the urea test/DMAC presumptive or confirmatory for urine?

Answer 34

presumptive

Question 35

describe the Urea test/DMAC

Answer 35

detects urea, turns pink if +ve

Question 36

What does faeces consist of?

Answer 36

- undigestible/indigested food - bacteria -mucus cells

Question 37

Describe the Urobilinogen test for faeces

Answer 37

- fluoresces orange, yellow, or green if positive - reagent added, then viewed under low wave UV

Question 38

How do we test for sweat?

Answer 38

- extract - prepare slide - microscopy for epithelial cells

Question 39

How do we test for vomit?

Answer 39

- smell lol - test or amylase, acids, microscopic food stuffs