With a 150 mL infusion over 60 minutes and a drop factor of 15 gtt/mL, what is the infusion rate in drops per minute?

With a 150 mL infusion over 60 minutes and a drop factor of 15 gtt/mL, what is the infusion rate in drops per minute?

• A. 25 gtt/min
• B. 38 gtt/min
• C. 50 gtt/min
• D. 60 gtt/min

Answer: (B)

Infusion rate in drops per minute is found by multiplying the volume in milliliters by the drop factor (drops per milliliter) and then dividing by the time in minutes. So with 150 mL over 60 minutes and a drop factor of 15 gtt/mL: 150 × 15 = 2250 drops total. Over 60 minutes, that’s 2250 ÷ 60 = 37.5 drops per minute. Since you can’t deliver half a drop, round to the nearest whole drop, giving 38 gtt/min.

Infusion rate in drops per minute is found by multiplying the volume in milliliters by the drop factor (drops per milliliter) and then dividing by the time in minutes. So with 150 mL over 60 minutes and a drop factor of 15 gtt/mL: 150 × 15 = 2250 drops total. Over 60 minutes, that’s 2250 ÷ 60 = 37.5 drops per minute. Since you can’t deliver half a drop, round to the nearest whole drop, giving 38 gtt/min.