Forensic Toxicology Flashcards
what are 2 things that are required in forensic toxicology?
patient consent
chain of custody
the application of chemical analytical procedures to isolate, extract, identify, and quantitate drugs and chemical in biological samples
forensic toxicology
what is the most widely used screening in forensic toxicology?
urine drug screen
what provides a qualitative result indicating the presence of a specific substance?
urine drug screen
what do urine drug screens detect?
class of the drug
what type of sensitivity and specificity does the initial urine drug screen show?
high sensitivity
low specificity
what is the gold standard for a urine drug confirmatory test?
gas chromatography with mass spectrometry (GC-MS)
what kind of sensitivity and specificity does the confirmatory urine drug test show?
high sensitivity
high specificity
what happens if you test below the drug cutoff levels on the initial urine drug screen?
lab cannot report as positive or get a confirmatory test
what happens if you test above the drug cutoff levels on the initial urine drug screen, but below them on the confirmatory test?
cannot be reported as positive
what is the most expensive and most intrusive biological specimen?
blood
what is the most accurate biological specimen for relating drug concentrations to clinical effects?
blood
what is the least common biological specimen of testing in forensic toxicology?
blood
what kind of blood specimen should be used in medical toxicology?
serum
plasma
what kind of blood specimen should be used in forensic toxicology?
whole blood
what is the specimen of choice for most tests?
urine
how do analytes in urine remain stable?
if frozen
what biological specimen is easy to administer but requires lab processing to ensure accuracy?
saliva
which biological specimen is useful for drugs that were used within the past few days?
saliva
what is the limitation in using saliva as a biological specimen for testing drugs?
only parent drug may be found
what is the stable biological specimen that measure long-term drug use, but does not detect recent drug use?
hair
how will a drug ingested today, appear on the scalp?
3cm above scalp in 3 months
stool collected through an amniocentesis
meconium
specimen that is sensitive for identifying infants who have been exposed to drugs in utero
meconium
what kind of drugs is meconium sensitive for?
basic and neutral drugs
what is the advantage of meconium specimen?
provides drug exposure info over 4-5 months of gestation
what are 2 limitations of testing meconium?
cannot detect acidic drugs
usually immunoassays (for specific compounds)
what are 2 specimen used in postmortem?
vitreous humor
stomach contents
biological sample that measures electrolytes, glucose, and alcohol postmortem
vitreous humor
substances that have a high potential for abuse and no accepted medical used and are not safe to use under medical supervision
schedule I
substances that have a high potential for abuse, despite having an accepted medicinal use in the US
schedule II
substances that have less potential for abuse but abuse can lead to moderate physical dependence or high psychological dependence
schedule III
substances than have less abuse potential and has accepted medical use in the US. Abuse may lead to limited physical or psychological dependence.
schedule IV
substances with limited quantities of certain narcotics that have less potential for abuse and and have accepted medical use in the US with limited risk of physical and psychological dependency
schedule V
what is the metabolite that is tested in marijuana?
carboxytetrahydrocannabinol
what is the detection time of marijuana in an occasional user?
3-5 days
what is the detection time of marijuana in a chronic user?
14 days
what is the detection time of marijuana in a “large” user?
30 days
what is the metabolite that is tested in cocaine?
benzolecgonine
methamphetamine is a derivative of endogenous _____
phenylethylamine (PEA)
where is methamphetamine present in? (2)
OTC inhaler
diet pills
what is the half-life of methamphetamine in acidic urine?
7-14 hours
what is the half-life of methamphetamine in alkaline urine?
18-34 hours
what is the half-life of heroin in blood?
< 20 mins
heroin has high _____ liability and high _____ solubility
addiction
lipid
what accounts for the activity of heroin?
morphine
what is the #1 cause of high toxicity levels?
polypharmacy
clinical signs and symptoms suggestive of a toxic reaction and indicates a medical emergency
toxidromes
what happens to pupil size with anti-cholinergics?
mydriasis (dilation)
what are 3 vitals with anti-cholinergics?
tachycardia
fever
hypertension
what is the mental status with anti-cholinergics?
mad as a hatter
what does the physical exam look like with anti-cholinergics?
dry as a bone
red as a beet
hot as a hare
urinary retention
what happens to pupil size with a cholinergic?
miosis (constriction)
what are 3 vitals with a cholinergic?
bradycardia
hypothermia
tachypnea
what is the mental status with a cholinergic?
altered mental status (confusion)
what does the physical exam look like with a cholinergic?
Salivation
Lacrimation
Urination
GI distress
Defecation
Emesis
