Worked example

IV drip rate (gtt/min) - practice problem 1

An order reads: infuse 250 mL of lactated Ringer's over 3 hours by gravity. The tubing drop factor is 15 gtt/mL.

Volume250 mL
Time3 hr
Drop factor15 gtt/mL

What is the drip rate in gtt/min?

Answer: 21 gtt/min

Step-by-step solution

1. Start from the flow rate and multiply by the drop factor
( 250 mL ÷ 180 min ) × ( 15 gtt ÷ 1 mL )
2. Cancel mL and solve
= ( 250 × 15 ) ÷ 180 gtt/min
= 20.83 gtt/min
3. Round to whole drops (you cannot count part of a drop)
20.83 gtt/min ≈ 21 gtt/min
= 21 gtt/min

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