CSPT - Compounded Sterile Preparation Technician Sterile Compounding Calculations 1

Question 1

A 500 mL bag of 0.9% sodium chloride is ordered to infuse over 4 hours using a 15 gtt/mL administration set. What is the required flow rate in drops per minute?

Accepted Answer

31 gtt/min

Answer

Flow rate (gtt/min) = (Volume × drop factor) ÷ time in minutes = (500 mL × 15 gtt/mL) ÷ (4 hr × 60 min/hr) = 7,500 ÷ 240 = 31.25, rounded to 31 gtt/min.

Question 2

A ceftriaxone 1 g powder vial is reconstituted with 9.6 mL of sterile water for injection, yielding a total volume of 10 mL. What is the resulting concentration?

Accepted Answer

100 mg/mL

Answer

Concentration = amount of drug ÷ final volume = 1,000 mg ÷ 10 mL = 100 mg/mL. Always use the final reconstituted volume, not the diluent volume added.

Question 3

A patient is ordered a heparin infusion at 1,200 units/hr. The bag is prepared as 25,000 units of heparin in 500 mL D5W. At what rate should the infusion pump be set?

Accepted Answer

24 mL/hr

Answer

First find the concentration: 25,000 units ÷ 500 mL = 50 units/mL. Then rate = dose ÷ concentration = 1,200 units/hr ÷ 50 units/mL = 24 mL/hr.

Question 4

How many mL of a 70% dextrose solution must be mixed with sterile water for injection to prepare 500 mL of a 10% dextrose solution?

Accepted Answer

71.4 mL

Answer

Using alligation: parts of 70% = (10 − 0) = 10 parts; parts of water = (70 − 10) = 60 parts; total = 70 parts. Volume of 70% solution = (10 ÷ 70) × 500 mL = 71.4 mL.

Question 5

A 60-kg patient requires gentamicin 2 mg/kg IV every 8 hours. The available vial is labeled 40 mg/mL. How many mL should be drawn up for each dose?

Accepted Answer

3.0 mL

Answer

Step 1 — calculate the dose: 2 mg/kg × 60 kg = 120 mg. Step 2 — calculate the volume: 120 mg ÷ 40 mg/mL = 3 mL per dose.

CSPT - Compounded Sterile Preparation Technician Practice Test

CSPT - Compounded Sterile Preparation Technician Practice Test

CSPT - Compounded Sterile Preparation Technician Sterile Compounding Calculations 1