Biological Evidence

Question 1

presumptive tests for blood

Answer 1

• Phenolphthalein: pink, reliable
• TMB: common, false positives
• Leucomalachite green: green, eliminates DNA
• Leuco Crystal Violet: violet, sensitive
• Luminol: 30-40s illumination, suspected carcinogen, eliminates DNA
• Fluorescein: possible carcinogen
• Hemastix: rapid and sensitive
• hemident: sensitive, eliminates DNA
• bluestar: illuminance last several minutes

Question 2

confirmatory tests

Answer 2

• Takayama: red feathery crystals
• Teichman reagent: brown-yellow rhomboid crystals
• Precipitin: antisera reactions
• ABA Card: hematrace strips

Question 3

blood typing

Answer 3

• not individualized but can exclude suspects

Question 4

CODIS

Answer 4

• FBI combined DNA index system
• uses 20 loci (specific location of gene sequences)

Question 5

Blood collection

Answer 5

• Liquid - dry swab, air dry
• Dry - wet swab, air dry, unless the object is portable

Question 6

Semen

Answer 6

• Contains high levels of SAP
• Presumptive: Acriflavine - fluoresces blue
• Confirmatory: microscopic ID, P30 test for vasectomies

Question 7

Saliva

Answer 7

• Presumptive: tests for amylase, however its found in many other things
• stains not usually evident, need a cup or cigarette

Question 8

Urine

Answer 8

• Presumptive tests for creatine, also in sweat
• no confirmatory

Question 9

Vomit

Answer 9

• No presumptive or confirmatory
• determine food and pH

Question 10

Vaginal Secretions

Answer 10

• Foreign DNA compared to samples from a penis or condom
• preserved by freezing