Toxicology Flashcards
(27 cards)
What does the toxicologist do?
analyze bodily fluids, tissues and organs or toxins and poisons and identify them
True or false: the toxicologist is employed only by crime labs?
False, often seen in clinical settings
What is the most abused drug in the West?
Ethyl Alcohol, most of the toxicologist job revolves around BAC
What is metabolism?
the transformation of chemicals into substances that are easier to eliminate - absorption, distribution and elimination
How is alcohol consumed in a full stomach absorbed differently than that on an empty stomach
Alcohol will be absorbed faster on an empty stomach, it is absorbed across the stomach, into the small intestine into the blood stream, then distributed to the watery parts of the body
How is alcohol eliminated from the body?
Oxidation: 95-98% converted in the liver into water and/or CO2
Excretion: removed in an unchanged state as breath, urine, sweat
What is the ratio of alcohol in the breath (alveolar) to alcohol in blood?
2100:1 ml
- basis of breathalyzers
- there is no direct proportion for brain:blood alcohol
At what rate is alcohol eliminated from the blood
0.015% w/v
In what time frame does alcohol in blood peak?
30-90 minutes, occurs at the end of absorption
Do roadside breath testers provide evidentiary results?
No, requires blood testing
What technology is used in breathalyzers?
- Infrared light absorption (detect and measure alcohol)
- fuel cell detectors (two platinum electrodes)
How do you avoid mouth alcohol in a breath test?
wait 15-20 minutes
What are the three psychophysical tests used in roadside tests?
- horizontal gaze nystagmus
- walk and turn
- one leg stand
How should blood samples be stored/transported?
- use an anticoagulant and preservative to maintain alcohol concentration
What is the most common lab test used to test blood for alcohol?
gas chromatography
What happens to heroin in the body?
it turns into morphine almost immediately
Most drugs can be classified chemically as what?
an acid or a base, thus drugs can be extracted by controlling the pH of the medium they are in
- acidic drugs will be extracted from acidified solutions
How are screening tests used?
- Give insight into the likelihood of a substance being in the sample
- Thin-layer chromatography
- GC
- Immunoassay (specific drug antibody reactions)
What are the most common confirmatory tests
GC and MS
What is the relation of drugs and hair?
- will diffuse from a capillary into a hair shaft
- becomes permanently trapped in hair, serves as a historical marker
- can estimate time as hair grows 1cm per month
- caution around environmental or sweat exposure
how does CO interact with blood?
- combines with hemoglobin forming carboxyhemoglobin
- interferes with the transportation of blood
How is poison detected in the blood?
- Heavy metals, only occasional encounters
- Reinsch test - dissolve tissue in HCL and insert a copper strip
- if a silver coating forms, the sample is positive for a poison
- confirm with emision spec. or x-ray diffr.
How does a roadside saliva test for THC work?
- strip coated with protons that bind to THC
- strip placed in an electronic reader that applies a voltage
- protons with THC have increases electrical current
How has the opioid crisis and designer drugs changes toxicology?
rapid development of naloxone kits and test strips to test for crossing/lacing
- challenge is that new variations are constantly made
