American Board of Toxicology
American Board of Toxicology
American Board of Toxicology
American Board of Toxicology
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October 7, 2017
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October 7, 2017
Santa Clara, California
October 7, 2017
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October 7, 2017
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October 7, 2017
Seoul, South Korea
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Raleigh, NC 27624

Phone: (919) 841-5022
Email: info@abtox.org

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The sample exam questions provided are derived from the 2004 and 2005 Recertification examinations, as well as the app. Please note,beginning in 2017, the exam will have four answer choices, not five. Happy practicing, and good luck!

Domain I: Design, Execute, and Interpret Toxicology Studies

1. What is the most likely result of administration by oral gavage of a test compound that is highly metabolized by the liver versus subcutaneous injection?
A) less parent compound present in the systemic circulation
B) more local irritation at the site of administration caused by the compound
C) lower levels of metabolites in the systemic circulation
D) more systemic toxicity
E) less systemic toxicity

2. In a reproductive toxicity study, what is the fertility index?
A) calculated as (number of pups alive at 4 days/number of pups born alive) x 100
B) represents the number of live fetuses per liter x 100
C) represents the percent of copulations that result in pregnancies
D) calculated as (number of fetuses at 14 days/total number of implantations) x 100
E) calculated as early fetal deaths/total implantations x 100

3. Which of the following best characterizes serum enzymes activities following hepatocellular injury?
A) serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities can increase within hours of significant liver injury
B) lactate dehydrogenase is liver specific
C) sorbitol dehydrogenase activity increases following injury to a broad variety of tissues
D) ALT is locally primarily in mitochondria
E) increased 5' nucleotidase activity occurs with both hepatocellular and biliary injury

4. The tester strains of Salmonella typhimurium used in the Ames Assay are which of the following?
A) TA 1535, TA 100, TA 1538, TA 98
B) TA 1540, TA 200, TA 1520, TA 80
C) TA 1548, TA 202, TA 1505, TA 92
D) TA 1536, TA 110, TA 1518, TA 85
E) TA 1510, TA 105, TA 536, TA 98

5. The in vivo micronucleus test is often used in a standard battery of genetic toxicity assays. In this test, the micronuclei are defined as which of the following?
A) pyknotic nuclei from a cell with decreased cytoplasmic to nuclear ratios
B) clumps of ribosomes
C) membrane-bounded structures that contain chromosomal fragments or whole chromosomes
D) binucleated remnants of germ cells
E) dense bodies of lysosomal origin

Answers to Domain I
1. A
2. C
3. A
4. A
5. C

Domain II: Descriptive Toxicology: Environmental, Clinical, Non-clinical, and Forensic Investigations

1. A patient is admitted to the emergency room with the following symptoms: dry mouth and skin; weak, rapid pulse (130 beats/min); elevated body temperature (103 degrees F); and mydriasis. He is excited and disoriented. In his pocket is a bottle of pills labelled: "take one as necessary for stomach pain". Of what is this patient is most likely to be suffering from an overdose?
A) a narcotic analgesic
B) a non-narcotic analgesic
C) an antacid
D) an antimuscarinic agent
E) a benzodiazepine tranquilizer

2. Which of the following poses the greatest food-borne risk world-wide?
A) chemical contaminants/adulterants
B) microbial contamination
C) additives from food processing/packaging
D) mycotoxins and molds
E) food additives

3. Which of the following is the most significant contributor to air pollution by mass in suburban areas?
A) manufacturing
B) transportation
C) space heaters
D) electric power generation
E) waste disposal

4. Drug X is available as a 2.5% solution for intravenous administration. The desired dosage of this drug is 5 mg/kg. What volume of drug should be injected if the patient weighs 50 kg?
A) 0.2 ml
B) 1.0 ml
C) 2.0 ml
D) 10 ml
E) 20 ml

5. Ethanol, retinoids, valproic acid, and the angiotensin converting enzyme (ACE) inhibitors all have which of the following effects?
A) cause liver toxicity
B) lower blood pressure
C) are human developmental toxicants
D) have central nervous system effects
E) have similar pharmacokinetic pathways

Answers to Domain II
1. D
2. B
3. B
4. D
5. C

Domain III: Mechanistic Toxicology

1. Which of the following ionizing radiations has the shortest range (i.e., travels the shortest distance in tissue) for the same initial energy?
A) alpha particle
B) beta particle
C) gamma ray
D) x ray
E) cosmic ray

2. Which property of compounds containing beryllium is the reason they are not readily absorbed from the gastrointestinal tract?
A) they form insoluble phosphate precipitates at the pH of the intestinal tract
B) they are chelated by bile salts in the small intestine
C) their size prevents passage through cell membranes
D) they are converted to an oxide form
E) exposures rarely occur to the soluble metallic form

3. Which of the following is NOT true regarding peroxisome proliferators?
A) they are a structurally diverse group of chemicals
B) they cause marked induction of lipid metabolizing enzymes
C) they often are non-genotoxic hepatocarcinogens in rodents
D) they induce hepatic CYP1A which is indicative of peroxisome proliferation
E) they operate via the peroxisome proliferator activated receptor

4. Which of the following is characteristic of a nongenotoxic carcinogen?
A) has no influence on the promotional stage of carcinogenesis
B) would be expected to produce positive responses in in vitro assays for mutagenic potential
C) typically exerts other forms of toxicity and/or disrupts cellular homeostasis
D) generally shows little structural diversity
E) typically has little effect on cell turnover

5. Based on the available data, cyclosporin A-induced cholestasis is most likely explained by which of the following?
A) interaction with the cytoplasmic receptor, cyclophilin
B) inhibition of transcription of message (mRNA) for critical cytokines
C) induction of programmed cell death in centrilobular hepatocytes
D) inhibition of ATP-dependent transporter(s) in the bile canalicular membrane
E) depolarization of the mitochondrial membrane potential

Answers to Domain III
1. A
2. A
3. D
4. C
5. D

Domain IV: Risk Assessment

1. Which of the following assumptions is NOT correct regarding risk assessment for male reproductive effects in the absence of mechanistic data?
A) an agent that produces an adverse reproductive effect in experimental animals is assumed to pose a potential reproductive hazard to humans
B) in general, a non-threshold is assumed for the dose-response curve for male reproductive toxicity
C) effects of xenobiotics on male reproduction are assumed to be similar across species unless demonstrated otherwise
D) the most sensitive species should be used to estimate human risk
E) reproductive processes are similar across mammalian species

2. Which of the following represents a measurable biochemical, physiological, or other alteration within an organism that indicates health impairment or disease?
A) biomarker of exposure
B) level of stress protein
C) biomarker of effect
D) bioavailable fraction
E) induction of CYP1A1

3. The reference dose (RfD) is generally determined by applying which of the following default procedures?
A) an uncertainty factor of 100 is applied to the NOAEL in chronic animal studies
B) a risk factor of 1000 is applied to the NOAEL in chronic animal studies
C) a risk factor of 10,000 is applied to the NOAEL in subchronic animal studies
D) an uncertainty factor between 10,000 and 1 million is applied to the NOEL from chronic animal studies
E) multiplying the NOAEL from chronic animal studies by 100

4. Which of the following concerning the use of the "benchmark dose" in risk assessment is NOT correct?
A) can use the full range of doses and responses studied
B) allows use of data obtained from experiments where a clear "no observed adverse effect level" (NOAEL) has been attained
C) may be defined as the lower confidence limit on the 10% effective dose
D) is primarily used for analyses of carcinogenicity data and has limited utility for analyses of developmental and reproduction studies that generate quantal data
E) is not limited to the values of the administered doses

5. Which of the following statements BEST describes the concept of perceived risk?
A) rarely incorporated into risk communication decisions
B) a relatively stable personal viewpoint that is not amenable to change
C) unrelated to the precautionary principle
D) highly influenced by factors such as familiarity and controllability
E) can be precisely measured and manipulated

Answers to Domain IV
1. B
2. C
3. A
4. D
5. D

Domain V: Applied Toxicology: Public, Environmental, and Occupational Health

1. What is the expected reaction of an individual exposed to 10 rads (0.1 Gy) of whole body x-irradiation?
A. severe bone marrow depression
B. death
C. permanent sterilization
D. no symptoms
E. vomiting

2. Which form of mercury was the predominant cause of Minamata Bay disease?
A) metallic mercury
B) mercuric salts
C) mercurous salts
D) organic mercury compounds
E) elemental mercury

3. Which of the following is CORRECT regarding the Delaney clause?
A) Permits food additives to be declared GRAS
B) Prohibits EPA from setting safe exposure levels to carcinogens
C) Prohibits FDA from approving food additives found to cause cancer
D) only applies to food additives demonstrating human evidence of carcinogenicity
E) has resulted in a wide range of banned food additives

4. What does a threshold limit value-time weighted average for a chemical represent?
A) an airborne concentration of a chemical that can never be exceeded
B) an airborne concentration of a chemical that is believed to cause no adverse health effect to a worker exposed for 8 hours a day, 40 hours a week
C) an airborne concentration of a chemical that cannot be exceeded for longer than 15 minutes a day
D) a value for an acceptable airborne concentration of a chemical established by the Occupational Safety and Health Administration
E) an airborne concentration which cannot be measured using available technology

5. Which is a target organ of streptomycin-induced toxicity?
A) lung
B) heart
C) reproductive system
D) kidney
E) liver

Answers to Domain V
1. D
2. D
3. C
4. B
5. D