ASCP Clinical Chemistry: Toxicology Questions

1. What is the formula to calculate serum osmolality?

A. (2 x K) + (Glucose ÷ 18) + (BUN ÷ 2.8)

B. (2 x Na) + (Glucose ÷ 18) + (BUN ÷ 2.8)

C. (Na x Glucose) ÷ BUN

D. (Na + K) ÷ Glucose

(2 x Na) + (Glucose ÷ 18) + (BUN ÷ 2.8)

2. A significant osmolal gap is defined as:

A. >5 mOsm

B. >8 mOsm

C. >10 mOsm

D. >15 mOsm

>10 mOsm

3. An increased oxygen saturation gap suggests:

A. Diabetes

B. Cyanide or carbon monoxide poisoning

C. Alcohol ingestion

D. Liver failure

Cyanide or carbon monoxide poisoning

4. Which toxic alcohol is metabolized to oxalate?

A. Methanol

B. Isopropyl alcohol

C. Ethylene glycol

D. Ethanol

Ethylene glycol

5. Which lab method specifically measures carboxyhemoglobin?

A. Pulse oximetry

B. Co-oximetry

C. Blood gas

D. ELISA

Co-oximetry

6. What does fomepizole inhibit?

A. Cytochrome P450

B. Glucuronyl transferase

C. Alcohol dehydrogenase

D. Aldehyde oxidase

Alcohol dehydrogenase

7. What are envelope-shaped crystals in urine associated with?

A. Acetaminophen poisoning

B. Ethylene glycol toxicity

C. Methanol ingestion

D. Lead poisoning

Ethylene glycol toxicity

8. Which metabolite of methanol causes toxicity?

A. Acetaldehyde

B. Formaldehyde and formic acid

C. Oxalate

D. Acetone

Formaldehyde and formic acid

9. What's the major toxic metabolite of acetaminophen?

A. Acetyl-CoA

B. Oxalate

C. NAPQI

D. Methanol

NAPQI

10. What antidote is used for acetaminophen toxicity?

A. N-acetylcysteine

B. Ethanol

C. Fomepizole

D. Sodium bicarbonate

N-acetylcysteine

11. Basophilic stippling is a hallmark of:

A. Arsenic toxicity

B. Cyanide poisoning

C. Lead poisoning

D. Methanol poisoning

Lead poisoning

12. Which enzyme does lead inhibit in heme synthesis?

A. Glucokinase

B. Delta-ALA dehydratase

C. Alcohol dehydrogenase

D. Tyrosinase

Delta-ALA dehydratase

13. Zinc protoporphyrin increases in:

A. Lead poisoning

B. Cyanide poisoning

C. Acetaminophen toxicity

D. Mercury poisoning

Lead poisoning

14. What is the most reliable test for chronic arsenic exposure?

A. Blood arsenic

B. Hair analysis

C. 24-h urine arsenic

D. CBC

24-h urine arsenic

15. Carboxyhemoglobin formation is associated with:

A. Ethanol

B. Carbon monoxide

C. Methanol

D. Lead

Carbon monoxide

16. Classic treatment for CO poisoning:

A. Fomepizole

B. Activated charcoal

C. 100% oxygen

D. Naloxone

100% oxygen

17. Cyanide inhibits which part of the ETC?

A. Complex II

B. Cytochrome a3

C. NADH dehydrogenase

D. ATP synthase

Cytochrome a3

18. A bright cherry red skin color is typical in:

A. Lead poisoning

B. Arsenic poisoning

C. Cyanide poisoning

D. Mercury poisoning

Cyanide poisoning

19. Which drug overdose can be evaluated using the Rumack-Matthew nomogram?

A. Salicylates

B. Acetaminophen

C. Methanol

D. Cocaine

Acetaminophen

20. Main metabolite of isopropyl alcohol:

A. Methanol

B. Acetone

C. Ethanol

D. Formic acid

Acetone

21. What is the earliest acid-base change in salicylate toxicity?

A. Metabolic acidosis

B. Respiratory alkalosis

C. Metabolic alkalosis

D. Mixed acidosis

Respiratory alkalosis

22. Metabolite detected in urine drug screens for cocaine:

A. Methadone

B. Benzoylecgonine

C. Codeine

D. THC

Benzoylecgonine

23. FEP and ZPP increase in:

A. B12 deficiency

B. Cyanide poisoning

C. Lead poisoning

D. Methanol toxicity

Lead poisoning

24. Mercury poisoning in children may present as:

A. Cyanosis

B. Acrodynia

C. Reticulocytosis

D. Muscle wasting

Acrodynia

25. What inhibits acetylcholinesterase in insecticides?

A. Arsenic

B. Cyanide

C. Organophosphates

D. Salicylates

Organophosphates

26. Typical lab finding in cyanide poisoning:

A. Low lactate

B. Elevated glucose

C. Elevated potassium

D. Hypocalcemia

Elevated glucose

27. Which metabolite is found in marijuana use?

A. Benzoylecgonine

B. 11-nor-THC-COOH

C. NAPQI

D. Methanol

11-nor-THC-COOH

28. The legal blood alcohol concentration limit is:

A. 20-40 mg/dL

B. 60-70 mg/dL

C. 80-100 mg/dL

D. 100-120 mg/dL

80-100 mg/dL

29. Antidote for cyanide poisoning includes:

A. Sodium thiosulfate

B. N-acetylcysteine

C. Deferoxamine

D. Ethanol

Sodium thiosulfate

30. Which metal inhibits mitochondrial enzymes and sulfhydryl enzymes?

A. Iron

B. Lead

C. Mercury

D. Arsenic

Lead

31. Which antidepressant class causes QRS prolongation in overdose?

A. SSRIs

B. MAOIs

C. TCAs

D. SNRIs

TCAs

32. Which alcohol causes blindness if untreated?

A. Ethanol

B. Methanol

C. Isopropanol

D. Ethylene glycol

Methanol

33. Lead exposure may cause:

A. Megaloblastic anemia

B. Sideroblastic anemia

C. Microcytic anemia with stippling

D. Hemolytic anemia

Microcytic anemia with stippling

34. What urinary findings suggest lead nephropathy?

A. Pyuria

B. Hematuria

C. Glycosuria and aminoaciduria

D. WBC casts

Glycosuria and aminoaciduria

35. What is Mees line associated with? (also called leukonychia striata) are smooth, transverse white bands of discoloration that run across the entire width of fingernails or toenails

A. Iron poisoning

B. Lead poisoning

C. Arsenic poisoning

D. Mercury poisoning

Arsenic poisoning

36. The best specimen for forensic ethanol testing:

A. Plasma

B. Serum

C. Breath

D. Whole blood

Whole blood

37. What causes birefringent envelope-shaped crystals in urine?

A. Lead

B. Ethylene glycol

C. Methanol

D. Salicylate

Ethylene glycol

38. GGT is a marker for:

A. Lead exposure

B. Liver fibrosis

C. Chronic alcohol consumption

D. Arsenic exposure

Chronic alcohol consumption

39. Which metabolite is responsible for salicylate toxicity?

A. Acetylsalicylic acid

B. Salicylic acid

C. Methanol

D. Formic acid

Salicylic acid

40. Which heavy metal causes erethism?

A. Arsenic

B. Mercury

C. Lead

D. Iron

Mercury

41. Fetal hemoglobin has high affinity for:

A. Ethanol

B. Acetone

C. CO

D. Lead

CO

43. What gives the bitter almond smell in poisoning?

A. Methanol

B. Cyanide

C. Ethanol

D. Acetone

Cyanide

44. Which compound uncouples oxidative phosphorylation in poisoning?

A. Salicylate

B. Methanol

C. CO

D. Lead

Salicylate

45. Which compound causes a bright red venous blood color?

A. Methanol

B. Lead

C. Cyanide

D. Acetaminophen

Cyanide

46. Which substance is not associated with metabolic acidosis?

A. Ethylene glycol

B. Methanol

C. Isopropyl alcohol

D. Cyanide

Isopropyl alcohol

47. Transverse white bands on nails indicate:

A. Iron deficiency

B. Lead poisoning

C. Arsenic poisoning

D. Mercury poisoning

Arsenic poisoning

48. Which poisoning is characterized by pinpoint pupils and bradycardia?

A. Salicylate

B. Organophosphate

C. Lead

D. Cyanide

Organophosphate

49. What's the classic sign of cocaine toxicity?

A. Bradycardia

B. Miosis

C. Mydriasis and hypertension

D. Cyanosis

Mydriasis and hypertension

50. A common source of arsenic is:

A. Batteries

B. Rubbing alcohol

C. Wood preservatives

D. Pesticide-free vegetables

Wood preservatives