A physician orders 1500 mcg of Vitamin B12. If the preparation is 1000 mcg per mL, how many milliliters should you administer?

A physician orders 1500 mcg of Vitamin B12. If the preparation is 1000 mcg per mL, how many milliliters should you administer?

• A. 0.75 ml
• B. 1.25 ml
• C. 0.50 ml
• D. 1.50 ml

Answer: (D)

To determine how much to give, use the relationship: Volume to administer = Dose desired ÷ Concentration. Here, the dose required is 1500 micrograms, and the preparation provides 1000 micrograms per milliliter. Divide 1500 by 1000 to get 1.5 milliliters. (Equivalently, 1500 mcg is 1.5 mg, and at 1 mg per milliliter, you’d use 1.5 mL.) Therefore, administer 1.5 milliliters.

To determine how much to give, use the relationship: Volume to administer = Dose desired ÷ Concentration. Here, the dose required is 1500 micrograms, and the preparation provides 1000 micrograms per milliliter. Divide 1500 by 1000 to get 1.5 milliliters. (Equivalently, 1500 mcg is 1.5 mg, and at 1 mg per milliliter, you’d use 1.5 mL.) Therefore, administer 1.5 milliliters.