How to Calculate Insulin Dosage: U-50 Insulin and U-100 Syringe
Understanding Insulin Dosage Calculation
Insulin administration is a critical aspect of the nursing profession, especially when dealing with different concentrations of insulin and syringe types. One common scenario that nurses encounter is when a patient is prescribed U-50 insulin but the nurse only has a U-100 syringe available. In such cases, proper dosage calculation is essential to ensure accurate medication administration.
Insulin Dosage Calculation Scenario
A patient has an order to receive 20 units of U-50 insulin. The nurse is using a U-100 syringe. How many units should the nurse draw up in the syringe and administer?
Options:
a. 0.04 mL
b. 0.4 mL
c. 4 mL
d. 10 mL
Final answer:
To administer 20 units of U-50 insulin using a U-100 syringe, the nurse should draw up and administer 0.4 mL (b). This is calculated by dividing the prescribed units by 2 because U-50 insulin has half the concentration of U-100 insulin.
Explanation:
The question is asking how much insulin to draw up in a U-100 syringe if the patient has an order to receive 20 units of U-50 insulin. The U-100 syringe is calibrated such that each “unit” measures out 1 unit of U-100 insulin, not U-50.
To calculate the dosage in a U-100 syringe for U-50 insulin, you divide the prescribed dosage (20 units of U-50 insulin) by 2. This is because U-100 insulin contains 100 units per milliliter (mL), and U-50 insulin contains 50 units per mL, hence U-50 insulin has a concentration that is half of that of U-100.
So, for U-50 insulin in a U-100 syringe, 1 unit is actually 0.02 mL (not the 0.01 mL it usually is for U-100 insulin). Therefore, the amount to draw up for 20 units = 20 x 0.02 mL = 0.4 mL. So, the answer is option b. 0.4 mL.