Clinical toxicology lab testing

Question 1

clinical applications of toxicology

Answer 1

1. Therapeutic drug monitoring
2. Acute management of overdose/Identification of illicit drug use
3. Monitoring of patient treatment compliance
4. Detection of exposure to environmental toxins

Question 2

forenscic applications of toxicology

Answer 2

1. Evidence for civil/criminal court cases
2. Investigation of cause of death
3. Workplace drug testing
4. High-level athletes

Question 3

reasons why toxicology testing is done

Answer 3

1. medical
2. forenscic

Question 4

practice of measuring the concentration of a drug or its metabolite in order to optimize the dosing of that drug to an individual patient and/or to assess patient compliance with a dosing schedule

Answer 4

therapeutic drug monitoring (TDM)

Question 5

goals of TDM

Answer 5

Maintain appropriate therapeutic effect
Monitor compliance
Avoid/minimize adverse effects

Question 6

indication of TDM is if the drug has a

Answer 6

low margin of safety

Question 7

indication of TDM is to verify patient

Answer 7

compliance

Question 8

indication of TDM is difficulty distinguishing sx of disease from

Answer 8

drug toxicity

Question 9

indication of TDM if prescribes drug has significant… as a result of :
Interindividual metabolic capacity
Frequent drug-to-drug interactions
Physiologic conditions such as aging or pregnancy
Underlying disease state such as liver or renal impairment

Answer 9

pharmacokinetic variability

Question 10

commonly monitored drugs

Answer 10

methotrexate
immunosuppressants
antibiotics
1st generation antiepileptics
2nd generation antiepileptics
tricyclic antidepressants
lithium
cardiac agents
pain management/addiction medicine

Question 11

TDM measures… typically through blood serum but may use urine and saliva

Answer 11

concentration of the drug and its metabolites in the body

Question 12

the time it takes for the concentration of the drug in the body to be reduced by half

Answer 12

drug half life

Question 13

use this rule to reach consistent steady-state of drug ex. 72 x 5 with bup

Answer 13

5 half life rule

Question 14

how long it takes for drug to clear sx

Answer 14

5 half lifes

Question 15

peak level of drug assess for

Answer 15

toxicity risk

Question 16

trough level assesses

Answer 16

therapeutic effect

Question 17

A folate antagonist used in the treatment of a wide variety of neoplasms

Answer 17

methotrexate

Question 18

adverse effects are:
Immunosuppression
Renal failure
Hepatic toxicity
Myelosuppression
GI toxicity
Death

Answer 18

methotrexate

Question 19

treats adverse effects of methotrexate

Answer 19

leucovorin

Question 20

TDM utilized to identify the minimum EFFECTIVE dose to decrease frequency and severity of seizures AND identify toxicity if present

Answer 20

antiepileptics

Question 21

Use to treat seizures, trigeminal neuralgia & bipolar disorder
Has slow and unpredictable absorption rates
Age and hepatic function affect drug clearance
Dose-related toxic effects include:
Blurred vision
Ataxia
Drowsiness
Nystagmus

Answer 21

carbamezepine (tegreol)

Question 22

peak level timing of carbamezepine (tegreol) to test for toxicity

Answer 22

2-4 hours

Question 23

Utilized to IDENTIFY past exposure or use of a drug
Typically only qualitative measurement is needed
Quantitative levels help determine USE of drug vs CONTAMINATION
Detects parent drug &/or drug metabolites
Basic vs Expanded Drug Screens
very sensitive. may just come from exposure

Answer 23

drugs of abuse testing (DAT)

Question 24

basic drug panel includes only 5 classes of drugs

Answer 24

amphetamines
opioids
cocaine
THC
PCP

Question 25

indications of DAT

Answer 25

Addiction Medicine Pain Management Psychiatric treatment Specific patient presentations: -Suspected overdose -Altered mental status -Seizures -Psychosis Forensic Purposes

Question 26

most common sample in DAT

Answer 26

urine

Question 27

step one of DAT

Answer 27

immunoassay test- is the drug present in the sample?

Question 28

step two of DAT

Answer 28

Confirmation testing via liquid or gas chromatography with mass spectrometry- how much of the drug is present in the sample?

Question 29

= the drug/metabolite of interest was present at or above the threshold concentration at the time the sample was obtained Step 2 will be POSITIVE

Answer 29

true positive result

Question 30

= “positive” reaction to specific cross-reacting medications or drugs are present in the sample Step 2 will be NEGATIVE

Answer 30

false positive results

Question 31

= the drug or metabolite of interest was not present at or above the threshold concentration at the time the sample was obtained Step 2 will be NEGATIVE or show TRACE amounts

Answer 31

true negative result

Question 32

= can occur for many reasons Consider adulteration of the sample

Answer 32

false negative result

Question 33

how pts alter drug screens

Answer 33

Urine dilution Masking agents Addition of adulterants “Spiking” of the urine sample Fake/”Borrowed” sample

Question 34

protocols to prevent tampering

Answer 34

Urine specific gravity requirements Temperature controlled specimen cups Observed specimen collection

Question 35

allows for clinical monitoring of patient compliance with prescribed treatment AND monitoring for use of non-prescribed/illicit drugs

Answer 35

combination TDM and DAT testing

Question 36

indications for combo testing

Answer 36

Addiction Medicine Chronic Opioid Therapy Chronic controlled substance therapy Stimulants Benzodiazepines

Question 37

purpose of combo testing

Answer 37

diagnostic and therapeutic purposes

Question 38

Presence of prescribed medications No identified other substances

Answer 38

expected results

Question 39

Lack of prescribed medications and/or Presence of other substances

Answer 39

unexpected results

Question 40

methamphetamine threshlod

Answer 40

250

Question 41

step 2 confirmation testing is to show

Answer 41

use vs contamination

Question 42

Addiction Medicine – Buprenorphine Patient X is currently being treated with medication assisted therapy (MAT) for Opioid Use Disorder (OUD) Current medications include: Buprenorphine/naloxone (Suboxone) 8/2mg films BID Fluoxetine (Prozac) 40mg daily Results of most recent urine drug screen: bup norbup and naloxone detected. alc and amphetamines not detected. expected?

Answer 42

yes

Question 43

bup and norbup detected. naloxone not detected

Answer 43

not expected

Question 44

bup detected, norbup not detected, naloxone detected

Answer 44

spiked urine. not expected

Question 45

commonly tested environmental toxin exposure

Answer 45

Carbon monoxide Lead Heavy metals Cyanide Insecticides