Presumptive Test for Blood - Answer--ID that blood is possibly present when results are positive
-eliminate stains from further consideration when test is negative
Presumptive vs Catalytic Color Test for Blood - Answer--presumptive test may be recognized as those which produce visible reaction ...
MSN 570 Final Exam Questions with
Latest Update
Presumptive Test for Blood - Answer--ID that blood is possibly present when results are
positive
-eliminate stains from further consideration when test is negative
Presumptive vs Catalytic Color Test for Blood - Answer--presumptive test may be
recognized as those which produce visible reaction or result in release of light
-catalytic color tests use chemical oxidation of chromogenic substance by an oxidizing
agent catalyzed in presence of blood: hemoglobin
Method of Performing a Presumptive Test for Blood - Answer--sample a stain with
clean, moistened cotton swab
-add drop of reagent
-add drop of hydrogen peroxide
-immediate development of color will show possible presence of blood
5 Types of Presumptive Tests for Blood - Answer--benzidine-adler test: blue-dark blue
when positive
-phenolphthalein-kastle-mayer test: pink when positive
-o-tolidine: blue when positive
-leucomalchite green (LNG): green when positive
-Hemastix: green / blue-green when positive
Chemiluminescence - Answer--process by which light is emitted as a product of
chemical reaction w/o emission of heat
-no other light is required like it is with luminol/bluestar
Fluorescence - Answer--occurs when chemical substance is exposed to particular
wavelength of light (short ones like UV) and light energy is emitted at longer
wavelengths
Luminol: How it reacts (2) and its uses (5) - Answer--reacts with heme producing a
chemiluminescence that has blue-green color
-reacts with other substances so a positive reaction is NOT CONCLUSIVE of presence
of blood
-when there are minute quantities of blood
-when blood is not readily available
-when scene has been cleaned
-when you need to differentiate b/t blood and other stain
-to assist in prioritizing evidence collection
, Bluestar - Answer--extremely sensitive
-blood detected on any background, material, animal, or vegetable in liquid or solid form
-blood may be detected either pure or diluted, while fresh, or long after it has been
deposited (dried or deteriorated)
-allows for viewing of blood traces even if they've been rinsed or cleaned
-does not destroy DNA
Fluorescein - Answer--works similarly to luminol or bluestar
-has commercial thickener and can adhere to vertical surfaces
-requires use of ALS set at 450nm
-will not fluoresce with household bleach - luminol does
Hematrace - Answer--confirmatory
-species-specific: shows positive for human and ferret
-put swab into buffer
-swab the stain
-put the swab back into buffer
-take pipet and put sample onto the S part of the litmus paper
-line by C or T will indicate positive or negative
-use these as leads more than anything
How many ml of fluid comes from one normal ejaculate?
How many spermatozoa in one ejaculate? - Answer--2.5 to 6 ml
-100 to 150 million
Presumptive (1) and Confirmatory (3) Tests for Seminal Fluid - Answer--presumptive
test: seminal acid phosphatase
-confirmatory tests: microscopic examination, prostate specific antigen, nuclear fast red
Seminal Acid Phosphate - Answer-*presumptive test only
-false positives in urine, vaginal secretions, sweat
-abundant in seminal plasma
-originates from epithelial cells which secrete the enzyme into prostate ducts
-stable enzyme
Steps of Brentamine Fast Blue Test - Answer-*a test for Seminal Acid Phosphate
1.Collect suspected semen stain with swab
2.Add Brentamine reagent
3.Reaction will cause intense purple color
-lack of color = negative test result
-thirty seconds = presence of semen likely
-two minutes = presence of contamination likely
Microscopic Examination of Seminal Fluid - Answer-*a confirmatory test
-microscopic ID of nonmotile spermatozoa
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