CSPT - Compounded Sterile Preparation Technician Sterile Compounding Calculations Questions and Answers — Questions and Answers
Question 1: A patient is to receive an IV infusion of 1 L of 0.9% Sodium Chloride over 8 hours. The administration set delivers 15 gtt/mL. What is the correct flow rate in drops per minute (gtt/min)?
- 21 gtt/min
- 125 gtt/min
- 8 gtt/min
- 31 gtt/min (Correct answer)
Correct answer: 31 gtt/min
First, calculate the total infusion time in minutes: 8 hours * 60 minutes/hour = 480 minutes. Next, calculate the total volume in mL: 1 L = 1000 mL. Use the formula: (Total Volume in mL / Total Time in minutes) * Drop Factor (gtt/mL) = Flow Rate (gtt/min). So, (1000 mL / 480 min) * 15 gtt/mL = 31.25 gtt/min. This is rounded to the nearest whole number, which is 31 gtt/min.
Question 2: A pharmacy technician needs to prepare 500 mL of a 2% (w/v) solution. The pharmacy stocks a 10% (w/v) concentrated solution. How many milliliters of the 10% stock solution are needed?
- 50 mL
- 100 mL (Correct answer)
- 200 mL
- 20 mL
Correct answer: 100 mL
This is a dilution calculation that can be solved using the formula C1V1 = C2V2, where C1 is the concentration of the stock solution, V1 is the volume of the stock solution, C2 is the concentration of the final solution, and V2 is the volume of the final solution. (10%) * V1 = (2%) * 500 mL. V1 = (2% * 500 mL) / 10%. V1 = 1000 / 10. V1 = 100 mL.
Question 3: A prescription requires 40 mEq of potassium chloride (KCl). The pharmacy has a stock vial of KCl with a concentration of 2 mEq/mL. How many milliliters of this solution should the technician draw?
- 10 mL
- 80 mL
- 20 mL (Correct answer)
- 40 mL
Correct answer: 20 mL
This is a direct dosage calculation. To find the required volume, divide the total required mEq by the concentration of the solution. Volume = Total mEq / Concentration (mEq/mL). Volume = 40 mEq / 2 mEq/mL = 20 mL.
Question 4: A technician must prepare 1000 mL of D10W (10% Dextrose in Water) using Sterile Water for Injection and D50W (50% Dextrose in Water). How much D50W is required?
- 500 mL
- 100 mL
- 800 mL
- 200 mL (Correct answer)
Correct answer: 200 mL
This problem can be solved using the allegation method or the C1V1=C2V2 formula. Using C1V1=C2V2: (50%) * V1 = (10%) * 1000 mL. V1 = (10 * 1000) / 50. V1 = 10000 / 50. V1 = 200 mL of D50W. The remaining volume (1000 mL - 200 mL = 800 mL) would be Sterile Water for Injection.
Question 5: An order is written for a patient weighing 165 lbs to receive a drug at a dose of 2 mg/kg. The drug is available in a vial with a concentration of 10 mg/mL. How many mL should be administered?
- 33 mL
- 7.5 mL
- 15 mL (Correct answer)
- 16.5 mL
Correct answer: 15 mL
First, convert the patient's weight from pounds (lbs) to kilograms (kg): 165 lbs / 2.2 lbs/kg = 75 kg. Next, calculate the total dose in mg: 75 kg * 2 mg/kg = 150 mg. Finally, calculate the volume in mL to administer: 150 mg / 10 mg/mL = 15 mL.
Question 6: How many grams of active ingredient are in 250 mL of a 1:500 (w/v) solution?
- 5 g
- 0.5 g (Correct answer)
- 2 g
- 50 g
Correct answer: 0.5 g
A ratio strength of 1:500 (w/v) means there is 1 gram of solute in 500 mL of solution. To find out how many grams are in 250 mL, you can set up a proportion: (1 g / 500 mL) = (x g / 250 mL). Solve for x: x = (1 g * 250 mL) / 500 mL. x = 0.5 g.
CSPT - Compounded Sterile Preparation Technician Sterile Compounding Calculations Questions and Answers
A patient is to receive an IV infusion of 1 L of 0.9% Sodium Chloride over 8 hours.
The administration set delivers 15 gtt/mL.
What is the correct flow rate in drops per minute (gtt/min)?