Forensics 1

Question 1

what is toxicology

Answer 1

analysis of body fluids and tissues for presences of drugs and poisons

Question 2

3 areas of forensic toxicology

Answer 2

postmortem: cause of death
human performance: drugs/poisons modifying human behaviour or performance
forensic drug testing: determine drug use

Question 3

knowledge required for a forensic toxicologist

Answer 3

drug metabolism
effects of poisoning on body
analytical chemistry
pharmacological action s

Question 4

toxicology role in death

Answer 4

homicide
suicide
accident
natural 
was there a drug, how much, when

Question 5

does toxicologist determine cause of death

Answer 5

no pathologist does

answers if the amount was sufficient to cause death

Question 6

info required to aid in interpretation in death

Answer 6

time and date of death
details of last meal
treated in hospital 
med history
symptoms
evidence at scene
time delay between death and autopsy

Question 7

what is postmortem redistribution

Answer 7

distribution of drugs from heart tssue to the cardiac blood
cardiac blood may be significantly elevated which may be good for preliminary investigations
changes start in 1h and usually done in 24hr

Question 8

more accurate blood level sites

Answer 8

femoral and cardiac may allow for more accurate interpretation of blood level at time of death

Question 9

some drugs that undergo postmortem redistribution

Answer 9

TCA

digoxin

Question 10

info to aid interpretation in living person

Answer 10

signs and symptoms
admission of drug or alcohol use
evidence found at scene

Question 11

4 stages of tox exam

Answer 11

1. screen - for as many drugs as possble with as little samples as possible
   confirm - 2 aliquots with different tests need to match
   quantification - need to use blood, liver, stomach
   interpret - toxic, therapeutic, lethal

Question 12

improper specimen selection, collection, and submission =

Answer 12

inaccurate results

Question 13

how to ensure continuity of exhibits

Answer 13

labelled by each possesser
sent by courier
adhesive tape to seal container
kept under lock and key
no access to lab to anyone unauthorized
transfer slips used

Question 14

types of blood samples and what they contain

Answer 14

serum
plasma - clotting factors
whole blood - RBC need to detect CO poisoning

Question 15

most reliable sample for alcohol and drug impairment

Answer 15

blood

Question 16

what is sodium fluoride

Answer 16

preservative to prevent breakdown of some drugs

Question 17

benefits of urine sample

Answer 17

non invasive
little to no sample prep
drugs/alcohol found in higher concentrations here
longer detection periods

Question 18

what is meant by urine having a long detection period

Answer 18

drug concentration that is detectable will be in the urine much longer than in the blood

Question 19

disadvantages of urine

Answer 19

may not reflect level of impairment at time of incident - not quantitative
some drugs break down in body so detection difficult
subject to tampering

Question 20

problems with cananbis detection in urine impairment vs probation

Answer 20

if used cannabis will be present in urine for long time

not able to convict someone of impaired driving but valid for someone who breached probation

Question 21

urine sample uses

Answer 21

used for identification
cant determine when or how much drug was taken (can be used to determine BAC if period over which urine was collected is known)
if refuse to provide sample = guilty

Question 22

hair sample advantages

Answer 22

noninvasive
easy to collect (crown of head)
no special storage requirements
useful in determining long term drug use

Question 23

disadvantages of hair samples

Answer 23

not useful for alcohol detection
costly
can be affected by environmental contamination (smoking)
racial and hair color bias - drugs incorporates more into dark hair than light
not useful for acute

Question 24

saliva collection method

Answer 24

expectorate into container
place cotton ball in mouth until saturated
may stimulate by chewing paraffin, rubber band, glass marble

Question 25

advantages of oral fluid sample

Answer 25

noninvasive
easy to collect
no medical personnal required to sample
drug detection time similar to blood
only parent drug detected

Question 26

disadvantages of oral fluid sample

Answer 26

requires sensitive analytical techniques
limited data regarding interpretation of oral fluid levels
recent smoking or oral consumption may complicate interpretation

Question 27

advantages of sweat sample

Answer 27

noninvasice
easy to collect with a patch
patch impermeable to environmental contaminants
tamper proof - has unique id number
only parent drug detected
(drug moves from body into patch)

Question 28

disadvantages of sweat sample

Answer 28

costly
requires sensitive methods for detection
entire patch consumed in analysis so cant retest
limit info regarding incorporation of drugs in sweat and significance in findings - only really used for probation

Question 29

samples used postmortem

Answer 29

blood 
urine
liver
stomach contents
bile
vitreous humor
CSF
kidnye
brain
lung
hair and fingernails
bone
heart
adipose tissue
site of injection

Question 30

explain blood collection post mortem

Answer 30

20ml from femoral and 20ml from cardiac
half of each sample in sodium fluoride to avoid breakdown of drugs and prevent formation of ethanol from bacteria
always whol eblood
often hemolyzed (RBC burst)

Question 31

advantages of liver sample

Answer 31

most valuble

drug accumuates here up to 100x the amount in blood

Question 32

liver may be only appropriate sample in

Answer 32

fire victims
babies
decomposed bodys

Question 33

what info might you gather from stomach contents

Answer 33

drug OD by oral ingestion
may be able to identify undissolved tablets
measure of unabsorbed drug at time of death
corrosive agents if erosion of stomach lining
detects parent drug not metabolites

Question 34

burnt almond smell =

Answer 34

cyanide

Question 35

garlic smell -

Answer 35

pesticides

Question 36

use for bile sample

Answer 36

waste product so just for identification not quantification

major route of elimination for some drugs - opiates, methadne, benzo

Question 37

what is vitreous humor used to detect

Answer 37

for alcohol when blood isnt good

not used for drugs

Question 38

advantages of vitreous humor sample

Answer 38

sterile environment so more true concentration
no putrefaction
clean sample

Question 39

disadvantage of vitreous humor sample

Answer 39

limited quantitiy

Question 40

when is CSF used

Answer 40

for alcohol when available
less subject to putrefaction and contamination
clean sample

Question 41

dis of CSF

Answer 41

limited quantity

diffficult to collect - spinal tap

Question 42

use kidney sample when

Answer 42

metal poisoning suspected

Question 43

use lung sample when

Answer 43

inhalation of poison

Question 44

samples less likely to use unless there is not a lot left to sample or unknown cause

Answer 44

kidney
brain
lung tissue
hair and fingernails
bone
heart
adipose tissue
sites of injection

Question 45

when does putrefaction occur and how to prevent

Answer 45

right away

freeze them

Question 46

carbon monoxide putrefaction

Answer 46

products interfere with analysis bc same UV spectrum

Question 47

cocain putrefaction issues

Answer 47

enzymes in blood continue to break down cocaine so then converted to inactive metabolite

Question 48

alcohol putrefaction issues

Answer 48

bacteria produces alcohol

Question 49

cyanide putrefaction issues

Answer 49

bacteria produce cyanide post mortem