10 exam-style questions with answers and explanations, straight from our 1,030-question bank. Tap an answer to check yourself. When you're ready, take the scored version in the free practice test.
The DABT exam has 160 questions and runs 4 hours.
These 10 free DABT questions are organized by exam domain, so you can see how each part of the Diplomate of the American Board of Toxicology (DABT) blueprint is tested. Reveal the answer and explanation under each question.
Rats receive 0, 15, 60, or 240 mg/kg/day for 90 days. Treatment-related renal tubular necrosis occurs at 60 and 240 mg/kg/day; serum creatinine increases only at 240. No treatment-related effects occur at 15. The renal lesions at 60 are absent after a recovery period. All other findings are non-adverse. Select the NOAEL for this study.
Correct answer: A - 15 mg/kg/day
A gavage study reports greater sedation at the nominal low dose than at the middle dose. Both suspensions were prepared from the same test-article batch. Pooled formulation assays meet concentration specifications, but the low-dose suspension stood for 45 minutes without documented mixing. Which check most directly tests whether unequal delivered concentrations explain the sedation pattern?
Correct answer: B - Compare top, middle, and bottom samples after the dosing hold.
Pregnant rats are individually randomized to vehicle or a test compound. Every fetus is weighed, and an initial analysis treats all fetal weights as independent observations. Which change most directly corrects the resulting statistical problem?
Correct answer: A - Model treatment as fixed and litter as a random effect.
A reactive vapor causes concentration-dependent nasal epithelial necrosis in an inhalation study. Circulating parent concentrations are very low. Oral dosing at a greater administered mass does not reproduce the nasal lesion. Which dose metric is most relevant when comparing the nasal findings?
Correct answer: D - Dose delivered to nasal tissue during inhalation.
Two adults are being evaluated for codeine treatment. Testing predicts minimal CYP2D6 activity in the first patient and markedly increased CYP2D6 activity in the second. Renal function is normal in both, and neither takes an interacting medicine. Compared with patients who have normal CYP2D6 activity, which response pattern is most likely?
Correct answer: C - First: reduced analgesia; second: greater respiratory-depression risk.
An investigational CD28 agonist binds purified human and cynomolgus receptors with similar affinity. Cynomolgus studies reach the anticipated human free-antibody exposure without cytokine release. A human-cell assay shows a strong inflammatory response at a matched free-antibody concentration. Which follow-up most directly investigates the species difference?
Correct answer: C - Compare CD28 expression and responses in corresponding CD4+ effector-memory T cells.
An asymptomatic copper-smelter employee has an elevated total urinary arsenic result after a weekend of shellfish meals. Workplace air-monitoring data are inconclusive. Which laboratory test would be most informative before assigning an occupational source?
Correct answer: D - Twenty-four-hour urinary arsenic speciation
Two adequately modeled studies of the same adverse endpoint each estimate a BMD10 of 10 mg/kg/day, where BMD10 is the dose associated with 10% extra risk. Their one-sided 95% lower confidence bounds are 2 mg/kg/day in Study A and 8 mg/kg/day in Study B. What does this comparison primarily indicate?
Correct answer: D - Study A has greater lower-tail uncertainty in its benchmark-dose estimate.
A 70-kg adult consumes 0.20 kg of fish containing 0.35 mg/kg of a contaminant and 0.10 kg of grain containing 0.70 mg/kg of the same contaminant every day. The applicable oral reference dose is 0.001 mg/kg/day. Assume these are the only exposures and use administered oral dose. Select the aggregate hazard quotient and its interpretation.
Correct answer: B - HQ = 2; the reference value is exceeded, without quantifying disease probability.
A parent and a 7-year-old child develop headache, nausea and confusion while using a malfunctioning fuel-burning heater indoors. At presentation, conventional pulse oximetry reads 99% in both. Oxygen is administered while testing is arranged. Which measurement most directly evaluates the suspected toxic exposure despite the apparently normal pulse-oximeter readings?
Correct answer: B - Blood carboxyhemoglobin measured by co-oximetry.
The full bank has 1,020 more DABT questions with explanations.
Continue in the free practice test →
View plans