Microdrip tubing delivers 60 drops per milliliter and is typically used for infusion rates less than 100 milliliters per hour. Which option matches this description?

• A. 60 gtt/mL; <100 mL/hr
• B. 10-15 gtt/mL; >100 mL/hr
• C. 60 gtt/mL; >200 mL/hr
• D. 10-15 gtt/mL; <50 mL/hr

Answer: (A)

Microdrip tubing has a drop factor of 60 drops per milliliter, so each milliliter delivered consists of 60 discrete drops. This higher drop factor allows more precise control at slower infusion rates, which is why it’s typically used for rates under 100 mL per hour. The correct pairing is 60 gtt/mL with a flow rate of less than 100 mL/hr because it matches both the drop factor and the preferred rate range for microdrip. The other options either use a lower drop factor (10–15 gtt/mL) that corresponds to macrodrip systems and faster infusions or propose flow rates above 100 mL/hr, which aren’t standard for microdrip.