CSPT Compounding Calculations 3 — Questions and Answers
Question 1: A compounded IV bag contains 3 g of vancomycin in 300 mL NS. What is the concentration in mg/mL?
- 1 mg/mL
- 10 mg/mL (Correct answer)
- 100 mg/mL
- 30 mg/mL
Correct answer: 10 mg/mL
3 g = 3000 mg; 3000 mg ÷ 300 mL = 10 mg/mL.
Question 2: A prescription requires 120 mL of a solution containing 15 mg/mL of drug X. How many grams of drug X are needed?
- 0.18 g
- 1.8 g (Correct answer)
- 18 g
- 180 g
Correct answer: 1.8 g
120 mL × 15 mg/mL = 1800 mg = 1.8 g.
Question 3: An insulin drip is running at 8 mL/hr. The bag contains 100 units in 100 mL NS. How many units per hour is the patient receiving?
- 4 units/hr
- 8 units/hr (Correct answer)
- 10 units/hr
- 16 units/hr
Correct answer: 8 units/hr
Concentration = 100 units/100 mL = 1 unit/mL; 8 mL/hr × 1 unit/mL = 8 units/hr.
Question 4: You need to prepare 200 mL of a 10% solution using pure drug powder. How much powder (in grams) is required?
- 2 g
- 10 g
- 20 g (Correct answer)
- 100 g
Correct answer: 20 g
10% w/v = 10 g/100 mL; for 200 mL: 10 × 2 = 20 g.
Question 5: A patient weighs 154 lbs. A drug is dosed at 2 mg/kg. What is the total dose in mg?
- 70 mg
- 140 mg (Correct answer)
- 154 mg
- 308 mg
Correct answer: 140 mg
154 lbs ÷ 2.2 = 70 kg; 70 kg × 2 mg/kg = 140 mg.
Question 6: A 1 L bag of D10W provides how many kilocalories from dextrose?
- 100 kcal
- 170 kcal
- 340 kcal (Correct answer)
- 400 kcal
Correct answer: 340 kcal
D10W = 10 g dextrose/100 mL = 100 g/L; dextrose provides 3.4 kcal/g; 100 g × 3.4 = 340 kcal.
Question 7: A USP <797> compounding record requires documenting beyond-use dates. A high-risk CSP stored at 2-8°C has a maximum BUD of:
- 12 hours
- 24 hours
- 3 days (Correct answer)
- 14 days
Correct answer: 3 days
USP <797> (2023) assigns a maximum 3-day BUD for Category 2 (formerly high-risk) CSPs stored at controlled cold temperature.
CSPT Compounding Calculations 3
A compounded IV bag contains 3 g of vancomycin in 300 mL NS.
What is the concentration in mg/mL?