Clinical Chemistry- Toxicology and Therapeutic Drug Monitoring Flashcards
1
Q
- In which of the following cases is qualitative
analysis of the drug usually adequate?
A. To determine whether the dose of a drug with a
low therapeutic index is likely to be toxic
B. To determine whether a patient is complying
with the physician’s instructions
C. To adjust dose if individual differences or disease
alter expected response
D. To determine whether the patient has been
taking amphetamines
A
D. To determine whether the patient has been
taking amphetamines
2
Q
- The term pharmacokinetics refers to the:
A. Relationship between drug dose and the drug
blood level
B. Concentration of drug at its sites of action
C. Relationship between blood concentration and
therapeutic response
D. The relationship between blood and tissue drug
levels
A
A. Relationship between drug dose and the drug
blood level
3
Q
- The term pharmacodynamics is an expression of
the relationship between:
A. Dose and physiological effect
B. Drug concentration at target sites and
physiological effect
C. Time and serum drug concentration
D. Blood and tissue drug levels
A
B. Drug concentration at target sites and
physiological effect
4
Q
- The study of pharmacogenomics involves which
type of testing?
A. Family studies to determine the inheritance of
drug resistance
B. Testing drugs with cell cultures to determine the
minimum toxic dosage
C. Testing for single nucleotide polymorphisms
known to affect drug metabolism
D. Comparison of dose-response curves between
family members
A
C. Testing for single nucleotide polymorphisms
known to affect drug metabolism
5
Q
- Select the five pharmacological parameters that
determine serum drug concentration.
A. Absorption, anabolism, perfusion, bioactivation,
excretion
B. Liberation, equilibration, biotransformation,
reabsorption, elimination
C. Liberation, absorption, distribution, metabolism,
excretion
D. Ingestion, conjugation, integration, metabolism,
elimination
A
C. Liberation, absorption, distribution, metabolism,
excretion
6
Q
- Which route of administration is associated with
100% bioavailability?
A. Sublingual
B. Intramuscular
C. Oral
D. Intravenous
A
D. Intravenous
7
Q
- The phrase “first-pass hepatic metabolism”
means that:
A. One hundred percent of a drug is excreted by
the liver
B. All drug is inactivated by hepatic enzymes after
one pass through the liver
C. Some drug is metabolized from the portal
circulation, reducing bioavailability
D. The drug must be metabolized in the liver to an
active form
A
C. Some drug is metabolized from the portal
circulation, reducing bioavailability
8
Q
- Which formula can be used to estimate dosage
needed to give a desired steady-state blood level?
A. Dose per hour = clearance (milligrams per hour)
× average concentration at steady state ÷ f
B. Dose per day = fraction absorbed – fraction
excreted
C. Dose = fraction absorbed × (1/protein-bound
fraction)
D. Dose per day = half-life × log Vd (volume
distribution)
A
A. Dose per hour = clearance (milligrams per hour)
× average concentration at steady state ÷ f
9
Q
- Which statement is true regarding the volume
distribution (Vd) of a drug?
A. Vd is equal to the peak blood concentration
divided by the dose given
B. Vd is the theoretical volume in liters into which
the drug distributes
C. The higher the Vd, the lower the dose needed to
reach the desired blood level of drug
D. The Vd is the principal determinant of the dosing
interval
A
B. Vd is the theoretical volume in liters into which
the drug distributes
10
Q
- For drugs with first-order elimination, which
statement about drug clearance is true?
A. Clearance = elimination rate ÷ serum level
B. It is most often performed by the liver
C. It is directly related to half-life
D. Clearance rate is independent of dose
A
A. Clearance = elimination rate ÷ serum level
11
Q
- Which statement about steady-state drug levels
is true?
A. The absorbed drug must be greater than the
amount excreted
B. Steady state can be measured after two
elimination half-lives
C. Constant intravenous infusion will give the same
minima and maxima as an oral dose
D. Oral dosing intervals give peaks and troughs in
the dose-response curve
A
D. Oral dosing intervals give peaks and troughs in
the dose-response curve
12
Q
- If too small a peak–trough difference is seen for a drug given orally, then:
A. The dose should be decreased
B. Time between doses should be decreased
C. Dose interval should be increased
D. Dose per day and time between doses should be
decreased
A
C. Dose interval should be increased
13
Q
- If the peak level is appropriate but the trough level
too low at steady state, then the dose interval
should:
A. Be lengthened without changing the dose
per day
B. Be lengthened and dose rate decreased
C. Not be changed, but dose per day increased
D. Be shortened, but dose per day not changed
A
D. Be shortened, but dose per day not changed
14
Q
- If the steady-state drug level is too high, the best
course of action is to:
A. Decrease the dose
B. Decrease the dose interval
C. Decrease the dose and decrease the dose interval
D. Change the route of administration
A
A. Decrease the dose
15
Q
- When should blood samples for trough drug levels
be collected?
A. 30 minutes after peak levels
B. 45 minutes before the next dose
C. 1–2 hours after the last dose
D. Immediately before the next dose is given
A
D. Immediately before the next dose is given
16
Q
- Blood sample collection time for peak drug levels:
A. Varies with the drug, depending on its rate of
absorption
B. Is independent of drug formulation
C. Is independent of the route of administration
D. Is 30 minutes after a bolus intravenous injection
is completed
A
A. Varies with the drug, depending on its rate of
absorption
17
Q
- Which could account for drug toxicity following a
normally prescribed dose?
A. Decreased renal clearance caused by kidney disease
B. Discontinuance or administration of another drug
C. Altered serum protein binding caused by disease
D. All of these options
A
D. All of these options
18
Q
- Select the elimination model that best describes
most oral drugs.
A. One compartment, linear first-order elimination
B. Michaelis–Menton or concentration-dependent
elimination
C. Two compartment with a biphasic elimination
curve
D. Logarithmic elimination
A
A. One compartment, linear first-order elimination
19
Q
- Drugs rapidly infused intravenously usually follow
which elimination model?
A. One compartment, first order
B. One compartment, logarithmic
C. Biphasic or two compartment with serum level
rapidly falling in the first phase
D. Michaelis–Menton or concentration-dependent
elimination
A
C. Biphasic or two compartment with serum level
rapidly falling in the first phase
20
Q
- Which fact must be considered when evaluating a
patient who displays signs of drug toxicity?
A. Drug metabolites (e.g., N-acetylprocainamide)
may need to be measured as well as parent drug
B. If the concentration of total drug is within
therapeutic limits, the concentration of free drug
cannot be toxic
C. If the drug has a wide therapeutic index, then it
will not be toxic
D. A drug level cannot be toxic if the trough is
within the published therapeutic range
A
A. Drug metabolites (e.g., N-acetylprocainamide)
may need to be measured as well as parent drug
21
Q
- When a therapeutic drug is suspected of causing
toxicity, which specimen is the most appropriate
for an initial investigation?
A. Trough blood sample
B. Peak blood sample
C. Urine at the time of symptoms
D. Gastric fluid at the time of symptoms
A
B. Peak blood sample
22
Q
- For a drug that follows first-order pharmacokinetics,
adjustment of dosage to achieve the desired blood
level can be made using which formula?
A. New dose = current dose/concentration at
steady state × desired concentration
B. New dose = current dose/desired
concentration × concentration at steady state
C. New dose = concentration at steady state/desired concentration × half-life
D. New dose = concentration at steady state/current dose × desired
concentration
A
A. New dose = current dose/concentration at
steady state × desired concentration
23
Q
- For which drug group are both peak and trough
measurements usually required?
A. Antiarrhythmics
B. Analgesics
C. Tricyclic antidepressants
D. Aminoglycoside antibiotics
A
D. Aminoglycoside antibiotics
24
Q
- Which of the following statements about TLC for
drug screening is true?
A. Acidic drugs are extracted in an alkaline
nonpolar solvent
B. A drug is identified by comparing its Rf value
and staining to standards
C. Testing must be performed using a urine sample
D. Opiates and other alkaloids are extracted at an
acid pH
A
B. A drug is identified by comparing its Rf value
and staining to standards
25
Q
- The EMIT for drugs of abuse uses an:
A. Antibody conjugated to a drug
B. Enzyme conjugated to an antibody
C. Enzyme conjugated to a drug
D. Antibody bound to a solid phase
A
C. Enzyme conjugated to a drug
26
Q
- Which statement about EMIT is true?
A. Enzyme activity is inversely proportional to drug
level
B. Formation of NADH is monitored at 340 nm
C. ALP is the commonly used conjugate
D. Assay use is restricted to serum
A
B. Formation of NADH is monitored at 340 nm
27
Q
- Which statement regarding cloned enzyme donor
immunoassay (CEDIA) is true?
A. The enzyme used is glucose-6-phosphate
dehydrogenase
B. The enzyme donor and acceptor molecules are
fragments of β-galactosidase
C. Drug concentration is inversely related to
fluorescence
D. The antibody is covalently linked to the enzyme
donor
A
B. The enzyme donor and acceptor molecules are
fragments of β-galactosidase
28
Q
- Which statement is true regarding particle-enhanced
turbidimetric inhibition immunoassay methods for
therapeutic drugs?
A. Drug concentration is proportional to light
scatter
B. Magnetic separation is needed to remove
unbound conjugate
C. When particle-bound drug binds to antibody,
light scattering is increased
D. Two antibodies to the drug are needed
A
C. When particle-bound drug binds to antibody,
light scattering is increased
29
Q
- Quantitation of a drug by gas chromatography–mass
spectroscopy (GC-MS) is usually performed in
which mode?
A. Total ion chromatography
B. Selective ion monitoring
C. Ion subtraction
D. Selective reaction monitoring
A
B. Selective ion monitoring
30
Q
- SITUATION: A urine sample is received in the
laboratory with the appropriate custody control
form, and a request for drug of abuse screening.
Which test result would be cause for rejecting
the sample?
A. Temperature after collection 95°F
B. pH 5.0
C. Specific gravity 1.005
D. Creatinine 5 mg/dL
A
D. Creatinine 5 mg/dL
31
Q
- Which substance has the longest detection time?
A. Amphetamines
B. Cocaine
C. Benzodiazepines
D. Marijuana
A
D. Marijuana
32
Q
- Which statement about the measurement of
carboxyhemoglobin is true?
A. Treatment with alkaline dithionite is used to
convert carboxyhemoglobin to oxyhemoglobin
B. Oxyhemoglobin has no absorbance at
540 nm, but carboxyhemoglobin does
C. Bichromatic analysis is required in order to
eliminate interference by oxyhemoglobin
D. Carboxyhemoglobin can be measured by
potentiometry
A
C. Bichromatic analysis is required in order to
eliminate interference by oxyhemoglobin
33
Q
- Which of the following statements about blood
alcohol measurement is correct?
A. Symptoms of intoxication usually begin when
the level exceeds 0.05% w/v
B. The skin puncture site should be disinfected
with isopropanol
C. The reference method is based upon enzymatic
oxidation of ethanol by alcohol dehydrogenase
D. Gas chromatography methods require extraction
of ethanol from serum
A
A. Symptoms of intoxication usually begin when
the level exceeds 0.05% w/v
34
Q
- Which specimen is the sample of choice for lead
screening?
A. Whole blood
B. Hair
C. Serum
D. Urine
A
A. Whole blood
35
Q
- Which of the following enzymes can be used to
measure plasma or serum salicylate?
A. Peroxidase
B. Salicylate esterase
C. Salicylate hydroxylase
D. p-Aminosalicylate oxidase
A
C. Salicylate hydroxylase
36
Q
- Which of the following tests is least essential to the
operation of an emergency department at a general
hospital?
A. Carboxyhemoglobin
B. Osmolality
C. Salicylate
D. Lead
A
D. Lead
37
Q
- Which of the following trace elements is
considered an essential micronutrient?
A. Thallium
B. Aluminum
C. Mercury
D. Selenium
A
D. Selenium
38
Q
- When measuring trace metals in blood other
than lead, what type of tube should be used?
A. Navy blue top
B. Green top
C. Purple top
D. Red top
A
A. Navy blue top
39
Q
- Which whole-blood level is suggestive of excessive
exposure to lead in children but not adults?
A. 4 μg/dL
B. 14 μg/dL
C. 28 μg/dL
D. 32 μg/dL
A
B. 14 μg/dL
40
Q
- What are the likely laboratory findings in a person
suspected of having Wilson’s disease?
A. Blood copper and ceruloplasmin low, urinary
copper excretion high
B. Blood and urine copper concentration high,
ceruloplasmin low
C. Blood and urine copper concentration high,
ceruloplasmin high
D. Blood and urine copper concentration low,
ceruloplasmin low
A
A. Blood copper and ceruloplasmin low, urinary
copper excretion high
