Examples Forensic toxicology

1 examples

1.1 urine
1.2 blood
1.3 hair sample
1.4 other
1.5 other organisms

examples
urine

a urine sample urine has come bladder , can provided or taken post-mortem. urine less infected viruses such hiv or hepatitis b blood samples. many drugs have higher concentration , can remain longer in urine blood. collection of urine samples can taken in noninvasive way not require professionals collection. urine used qualitative analysis cannot give indication of impairment due fact drug presence in urine indicates prior exposure.

blood

a blood sample of approximately 10 ml (0.35 imp fl oz; 0.34 us fl oz) sufficient screen , confirm common toxic substances. blood sample provides toxicologist profile of substance subject influenced @ time of collection; reason, sample of choice measuring blood alcohol content in drunk driving cases.

hair sample

hair capable of recording medium long-term or high dosage substance abuse. chemicals in bloodstream may transferred growing hair , stored in follicle, providing rough timeline of drug intake events. head hair grows @ rate of approximately 1 1.5 cm month, , cross sections different sections of follicle can give estimates when substance ingested. testing drugs in hair not standard throughout population. darker , coarser hair more drug found in hair. if 2 people consumed same amount of drugs, person darker , coarser hair have more drug in hair lighter haired person when tested. raises issues of possible racial bias in substance tests hair samples.

other

other bodily fluids , organs may provide samples, particularly samples collected during autopsy. common autopsy sample gastric contents of deceased, can useful detecting undigested pills or liquids ingested prior death. in highly decomposed bodies, traditional samples may no longer available. vitreous humour eye may used, fibrous layer of eyeball , eye socket of skull protects sample trauma , adulteration. other common organs used toxicology brain, liver, , spleen.

the inspection of contents of stomach must part of every postmortem examination if possible because may provide qualitative information concerning nature of last meal , presence of abnormal constituents. using guide time of death, however, theoretically unsound , presents many practical difficulties, although may have limited applicability in exceptional instances. generally, using stomach contents guide time of death involves unacceptable degree of imprecision , liable mislead investigator , court. characteristic cell types food plants can used identify victim s last meal; knowledge can useful in determining victim s whereabouts or actions prior death (bock , norris, 1997). of these cell types include (dickison, 2000):

sclereids (pears)
starch grains (potatoes , other tubers)
raphide crystals (pineapple)
druse crystals (citrus, beets, spinach)
silica bodies (cereal grasses , bamboos)

in case young woman had been stabbed death, witnesses reported had eaten last meal @ particular fast food restaurant. however, stomach contents did not match limited menu of restaurant, leading investigators conclude had eaten @ point after being seen in restaurant. investigation led apprehension of man whom victim knew, , whom had shared actual final meal (dickison, 2000). time since death can approximated state of digestion of stomach contents. takes @ least couple of hours food pass stomach small intestine; meal still largely in stomach implies death shortly after eating, while empty or nearly-empty stomach suggests longer time period between eating , death (batten, 1995). however, there numerous mitigating factors take account: extent food had been chewed, amount of fat , protein present, physical activity undertaken victim prior death, mood of victim, physiological variation person person. these factors affect rate @ food passes through digestive tract. pathologists hesitant base precise time of death on evidence of stomach contents alone.

other organisms

bacteria, maggots , other organisms may have ingested subject matter may have ingested toxic substance within it.