Forensic Toxicology Overview Flashcards
What is toxicology?
- the analysis of body fluids and tissues for the presence of drugs and poisons
- involves ID
- involves quantification
- involves interpretation
What is postmortem forensic toxicology?
- determines the cause and manner of death
- analysis of body fluids and tissues
What is human performance forensic toxicology?
- modifying human performance of behaviour
- analysis of blood, breath or urine
What is forensic drug testing?
- determine drug use
- analysis of urine, oral fluid, sweat or hair
What questions will a forensic toxicologist answer?
- was a drug/poison found
- what was found
- how much was found
- was the amount of poison/drug sufficient to cause death
- when and how was the poison taken into the body
What is the information that is required to aid in interpretation?
- age, gender and weight
- time and date of death/incident
- details of the last meal; actions between meal and onset of sx
- was person treated in hospital
- medication and drinking history
- time delay between death and autopsy
What is postmortem redistribution?
- involves the distribution of drugs from the heart tissue to the cardiac blood
- cardiac blood levels may be significantly elevated
- levels from 2 sites (femoral and cardiac) allow for more accurate interpretation
What information is required when interpreting a crime from a living person?
- age, gender and weight
- s/s of impairment or intoxication
- admission of drug and alcohol use
- evidence found at the scene or on the victim of the accused
What is the toxicology exam?
- screen or tentative ID
- confirmation
- quantitation
- interpretation
What is blood the most reliable sample for interpretation of?
- alcohol and drug impairment
What is good about urine sample detection?
- urine provides a longer period of detection
- convenient to collect, non invasive
- DRUGS ARE FOUND IN HIGHER CONCENTRATIONS HERE
What is the downside of urine collection?
- may not reflect the level of impairment at the time of the incident
- some drugs may break down in the body, making ID more difficult
- may be subject to tampering
What are the limitations to urine testing?
- used for ID purposes
- cannot determine WHEN or HOW MUCH drug was taken
What is hair testing useful for?
- non-invasive
- no special storage requirement
- useful in determining long term drug use
Can you detect alcohol from a blood sample?
- NO (environmental contamination may also be an issue)
What is oral fluid drug detection times similar to?
- similar to blood
- only the parent drug here will be detected
Is sweat a useful way of determining drug levels?
not really-costly, requires sensitive methods for detection
- entire patch is consumed in analysis
- limited info collected- only parent drug is detected here
What is one of the most valuable tissues for post-mortem drug analysis?
- LIVER
Drugs accumulate in the liver ________ the concentration found in the blood
100x
When is stomach contents an important thing to examine?
- when drug overdose by oral ingestion if suspected
- by visual inspection: may be able to ID undissolved or undigested tablets
- is a measure of unabsorbed drug at the time of death
What drug is bile a major rout of elimination for?
- opiates
Bile samples cannot determine ________ or ________
when or how the drug was consumed
What is vitreous humour routinely analyzed for?
- alcohol not drugs
Vitreous humour is less subject to what?
- contamination and putrefaction
- limited quantity available
CSF fluid is analyzed for what?
- alcohol when available (less subject to contamination and putrefaction)
What is the alcohol concentration in the blood when someone starts to decompose?
200 mg %
What are some chemicals that putrefaction can cause some challenges in the analysis of?
- CO
- cocaine
- alcohol
- cyanide
What should you do if examination of submission is going to be delayed?
- FREEZE
