Rationale of the Week | U-500 Insulin Still Causing Confusion

For our May 25th Question of the Week, 71% of respondents chose the best answer, which is awesome! However, for safety and teaching purposes, we still want to “take a closer look” at this question at aim for 100% correct responses the next go around.

Before we start though, if you don’t want any spoilers and haven’t tried the question yet, you can answer below: Answer Question

Question: Mr. J is started on 100 units U-500 twice a day.

Which of the following administration techniques would ensure he gets the right dose?

Answer Choices:

  1. Using a U-100 syringe, withdraw 100 units.
  2. Using a U-500 syringe, withdraw 20 units.
  3. Using a U-500 pen, dial to 100 units.
  4. Using a U-500 pen, covert to 20 units.

As shown above, the most common choice was option 3, the second most common answer was option 2, then option 4, and finally option 1.

Getting to the Best Answer

If you are thinking about taking the certification exam, the content of this practice test question will set you up for success. The exam will present questions that require test takers to be familiar with accurate dispensing of diabetes medications, injectables and insulins, including the concentrated versions.

Answers & Rationale

Answer 1 is incorrect, 7.11% chose this answer, “Using a U-100 syringe, withdraw 100 units.” This answer is wrong because when withdrawing U-500 insulin from a vial, a U-500 insulin syringe must be used (see image). Since U-500 insulin is 5x’s the concentration of U-100 insulin, drawing up 100 units of U-500 insulin in a U-100 syringe would deliver 500 units of insulin (or 5x’s too much and could be life threatening). See Concentrated insulin card below.

When using a U-500 syringe, no conversion is needed since the syringe automatically delivers the correct dose of U-500 insulin. No conversion, calculations or adjustments required.

U-500 Insulin Syringe Features

Answer 2 is incorrect, 12.64% of you chose this answer, “Using a U-500 syringe, withdraw 20 units.” When using a U-500 syringe, no conversion is needed since the syringe automatically delivers the correct dose of U-500 insulin. No conversion, calculations or adjustments required. For example, if the order reads “100 units of U-500 concentrated insulin twice a day”, using a U-500 syringe, the person would withdraw 100 units of U-500 insulin.

Answer 3 is correct, 71.25% of you chose this answer, “Using a U-500 pen, dial to 100 units.” YES, GREAT JOB! If the order reads “100 units of U-500 concentrated insulin twice a day”, using a U-500 pen, the person would dial to 100 units of U-500 insulin. The pens automatically deliver the correct dose in less volume. No conversion, calculations or adjustments required.

Answer 4 is incorrect, 9.00% of you chose this answer, “Using a U-500 pen, covert to 20 units.” When using a U-500 pen, no conversion is needed since the U-500 pen is specifically created to deliver the correct dose of U-500 insulin. For example, if the order reads “100 units of U-500 concentrated insulin twice a day”, using a U-500 pen, the person would dial to 100 units of U-500 insulin.

We hope you appreciate this week’s rationale! Thank you so much for taking the time to answer our Question of the Week and participate in this fun learning activity!


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