Blood Detection and Enhancement

Question 1

Give examples of presumptive tests.

Answer 1

Hemastix
Hemident
Hexagon OBTI
Kastle Meyer test

Question 2

Describe Hemastix.

Answer 2

3’ plastic strips with a reagent material at the tip

Question 3

How does the Hemastix reaction work?

Answer 3

Reagent at tip detects the peroxide-like activity of hemoglobin

Question 4

What happens when Hemastix detects hemoglobin?

Answer 4

Tip turns green

Question 5

What is a limitation of Hemastix?

Answer 5

Cannot differentiate between human and animal blood

Question 6

Describe Hemident.

Answer 6

Disposable tube containing two chemical reagent ampoules
Swab of stain is placed inside tube and both ampoules are broken

Question 7

What is an indication of blood in Hemident?

Answer 7

Blue/green reaction

Question 8

What is a limitation of Hemident?

Answer 8

Does not distinguish between human and animal blood

Question 9

What is another name for Hemident?

Answer 9

McPhail’s Reagent

Question 10

Describe how Hexagon OBTI works.

Answer 10

Swab added into transport medium
Medium added to test bar

Question 11

What does two lines mean in Hexagon OBTI?

Answer 11

Human origin

Question 12

Up to how much dilution can Hexagon OBTI detect blood?

Answer 12

1:1,000,000

Question 13

How many red blood cells are required for a positive Hexagon OBTI result?

Answer 13

As few as 500 RBCs required

Question 14

What is another name for the Kastle Meyer test?

Answer 14

Phenolphthalein

Question 15

Outline the 3 solution process of the Kastle Meyer test.

Answer 15

Moistent swab with solution A
Swab stain
Add 1-2 drops of Sol B (Phenolphthalein)
Add 1-2 drops of Sol C (hydrogen peroxide solution)

Question 16

Describe what an inconclusive Kastle-Meyer result would look like.

Answer 16

Delayed reaction (takes more than 30 seconds)
Swab turns pink before addition of the hydrogen peroxide solution

Question 17

Describe what a positive Kastle Meyer result would look like.

Answer 17

Swab turns pink after the addition of the peroxide solution

Question 18

Describe what a negative Kastle Meyer test would look like.

Answer 18

No pink colour change
No reaction after addition of peroxide solution

Question 19

What is a limitation of the Kastle Meyer test?

Answer 19

Not specific for blood; some materials can give false positives

Question 20

Give exmaples of material that can lead to a false positive in the Kastle Meyer test.

Answer 20

Plant matter (ex. broccoli, horseradish, potatoes)
Bleach
Some soaps and disinfectants
Rust or metal oxides
Some adhesives and glues

Question 21

What is done after a presumptive blood test?

Answer 21

Confirmatory testing - swabs are sent to CFS for analysis.

Question 22

Differentiate between blood dectection and enhancement.

Answer 22

Detection of blood is finding that blood is present.
Enhancement is the act of increasing its visibility.

Question 23

What factors should be considered when detecting or enhancing blood?

3

Answer 23

Necessity
Health and safety
Interference with other examinations

Question 24

List some things to be considered when deciding if blood enhancement and/or detection is necessary.

5

Answer 24

What is that stain?
Is it already visible/detectable as is?
What is the best option?
What benefit can be achieved by doing it?
Preference or direction from BPA ANalyst

Question 25

What should be considered in terms of the health and safety of blood enhancement/detection? | 5

Answer 25

Is it carcinogenic? What PPE is required? Does the area require evacuation? Is it flammable? Clean up

Question 26

What should be considered when determining if a blood detection/enhancement method will interfere with other examinations? | 5

Answer 26

Where are you going to do this? How can that be achieved? What potential interference can occur? Will it affect the stain? Dilution

Question 27

List blood detection and enhancement methods from least to most destructive.

Answer 27

Visual (available light) Visual (white light, ALS, laser) Blood locaters and enhancers

Question 28

When are enhancement chemicals used?

Answer 28

When there is visible blood and some type of pattern is suspected.

Question 29

How do enhancement chemicals work? Are they blood specific?

Answer 29

They stain the protein component of blood, not specific for blood

Question 30

Are enhancement chemicals considered presumptive testds?

Answer 30

No

Question 31

What must be collected before blood is enhanced? | 3

Answer 31

Photos DNA samples Presumptive test

Question 32

List the enhancement chemicals discussed in class. | 6

Answer 32

Hungarian red Acid yellow Amido black Coomassie Blue LCV LMG

Question 33

What type of stain is Hungarian Red?

Answer 33

Protein stain

Question 34

On what type of surfaces is Hungarian Red suitable for blood enhancement?

Answer 34

Non-porous surfacs

Question 35

What colour of staining does Hungarian Red result in?

Answer 35

Red/purple stain

Question 36

What are the 3 steps for Hungarian Red enhancement?

Answer 36

Fixative Dye application Rinse

Question 37

Can Hungarian Red be lifted? If so, with what?

Answer 37

Can be lifted with gel lifter

Question 38

Describe how Hungarian red fluoresces.

Answer 38

Can fluoresce with green light (505-530 and red filter)

Question 39

What kind of stain is Acid Yellow?

Answer 39

Protein stain

Question 40

On what type of surfaces is acid yellow suitable?

Answer 40

Non-porous surfaces

Question 41

What colour stain is produced by Acid Yellow?

Answer 41

Yellow stain

Question 42

Does acid yellow require an ALS?

Answer 42

Yes

Question 43

Outline the 3 steps for enhancement with acid yellow

Answer 43

Fixative Dye application Rinse

Question 44

Describe ALS requirements for acid yellow

Answer 44

Fluoresces with blue (450 nm) light and orange filter

Question 45

What type of stain is amido black?

Answer 45

Protein stain

Question 46

On what type of surfaces is amido black suitable?

Answer 46

Porous or non-porous surfaces

Question 47

What colour does amido black produce?

Answer 47

Blue-black colour

Question 48

What are the three steps for amido black enhancement?

Answer 48

Fixative Dye application Rinse

Question 49

What should be kept in mind about amido black?

Answer 49

May stain surfaces

Question 50

Does amido black require ALS?

Answer 50

No

Question 51

What kind of stain is Coomassie Blue?

Answer 51

Protein stain

Question 52

On what type of surfaces is Coomassie Blue suitable?

Answer 52

Porous and non-porous

Question 53

What stain results from Coomassie Blue?

Answer 53

Blue stain

Question 54

Does Coomassie Blue require an ALS?

Answer 54

No

Question 55

Outline the process of Coomassie Blue enhancement

Answer 55

Dip or spray with reagent Rinse with provided rinse

Question 56

What fixative is used if water is the main solvent in the dye?

Answer 56

5-sulphosalicylic acid

Question 57

What fixative is used if methanol is the main solvent in the dye?

Answer 57

Methanol

Question 58

What is the purpose of the rinse on non-porous surfaces?

Answer 58

Removes excess dye

Question 59

What is the purpose of the rinse on porous surfaces?

Answer 59

Destainer

Question 60

How does leucocrystal violet work?

Answer 60

Reacts with heme in red blood cells

Question 61

On what type of surfaces is LCV suitable?

Answer 61

Porous or non-porous

Question 62

How is LCV applied?

Answer 62

SPray

Question 63

What colour is produced by LCV?

Answer 63

Purple/violet

Question 64

Describe how the LCV reaction progresses/

Answer 64

Oxidation occurs slowly with influence of light, development is not permanent and background can also develop over time

Question 65

What colour is produced by leucomalachite green?

Answer 65

Green

Question 66

List the search chemicals for blood detection. | 3

Answer 66

Luminol Bluestar LCV

Question 67

How does luminol work?

Answer 67

Iron in blood catalyzes luminescence

Question 68

What is the purpose of luminol?

Answer 68

FInd traces of blood even if someone has attempted to clean or remove

Question 69

How is luminol applied?

Answer 69

SPray

Question 70

True or false: Luminol can be used in the light and the dark.

Answer 70

Flase, needs to be done in darkness

Question 71

How long does the blue glow of luminol last?

Answer 71

30 seconds

Question 72

How is the effects of luminol documented?

Answer 72

Long-exposure

Question 73

What is an important consideraiton for luminol?

Answer 73

Tends to lose fine detail

Question 74

Compare Bluestar to Luminol.

Answer 74

Based on Luminol but requires no chemical mixing

Question 75

How is Bluestar prepared?

Answer 75

Tablets dissolved in water

Question 76

How does Bluestar work?

Answer 76

Reacts with heme in red blood cells

Question 77

How is Bluestar applied?

Answer 77

Spray

Question 78

What is an important consideration for Bluestae?

Answer 78

Tends to lose fine detail

Question 79

What materials can give false positives for Luminol and Bluestar? | 4

Answer 79

Plant peroxidases Chemical oxidants Certain cleaning materials Metals

Question 80

Does Bluestar require complete darkness?

Answer 80

No

Question 81

What happens to luminescence during second application of Luminol? Bluestar?

Answer 81

Diminished in luminol, maintained in Bluestae

Question 82

Are Luminol and Bluestar DNA destructive?

Answer 82

No

Question 83

What is the shelf life of Luminol after mixing?

Answer 83

None

Question 84

What is the shelf life of Bluestar after mixing?

Answer 84

Can be used for several days

Question 85

Is laboratory preparation needed for Luminol?

Answer 85

Yes

Question 86

Describe how to photograph Luminol and Bluestar. | 3

Answer 86

Tripod Photograph in ambient light, darken room and do not move camera Overlay photographs