If 0.25 mL is drawn from the vial, how many milligrams are delivered?

If 0.25 mL is drawn from the vial, how many milligrams are delivered?

• A. 0.25 mg
• B. 0.75 mg
• C. 3.75 mg
• D. 3 mg

Answer: (C)

The key idea is converting a drawn volume into the amount of drug using the vial’s labeled concentration. You multiply the volume drawn (in mL) by the concentration (in mg per mL) to get the dose in mg. If the vial is 15 mg/mL and you draw 0.25 mL, the calculation is 0.25 × 15 = 3.75 mg, so 3.75 mg is delivered. If the concentration were different, the mg delivered would change accordingly—for example, 1 mg/mL would yield 0.25 mg with 0.25 mL, 3 mg/mL would yield 0.75 mg, and 12 mg/mL would yield 3 mg.

The key idea is converting a drawn volume into the amount of drug using the vial’s labeled concentration. You multiply the volume drawn (in mL) by the concentration (in mg per mL) to get the dose in mg. If the vial is 15 mg/mL and you draw 0.25 mL, the calculation is 0.25 × 15 = 3.75 mg, so 3.75 mg is delivered. If the concentration were different, the mg delivered would change accordingly—for example, 1 mg/mL would yield 0.25 mg with 0.25 mL, 3 mg/mL would yield 0.75 mg, and 12 mg/mL would yield 3 mg.