Explaining Active Insulin

Active insulin is a type of insulin that is out-going, heavily involved in sports and enjoys outdoor activities.

This is false – it’s actually an interesting and really important insulin pump feature included in the Bolus Wizard™ feature of the MiniMed™ insulin pumps! If you use the Bolus Wizard™ and you are still not sure what active insulin is or how it's calculated, this information is important and helpful for you. Have you ever noticed that you tried to bolus through the Bolus Wizard™ and it changed the estimated amount of insulin you need? This is because of “active insulin”.

Let’s start with a word problem. What is the estimated total amount of insulin that will be delivered by your pump if, you entered:

• A blood glucose (BG) value of 11.1 mmol/L
• 60 grams of carbohydrates
• Background settings of a 1:10 carb ratio
•  5.5 mmol/L BG target
• And an insulin sensitivity of 2.5:1

If you said 8 units of insulin, you’d be right… unless you still have 2 units of insulin in your body from a previous bolus. Then, you only need 6 units instead of 8 units. As you know, this can make a big difference in your blood glucose. Those 2 units from your last bolus – that’s “active insulin”.

The Bolus Wizard™ feature is able to change bolus recommendations in cases like this one, when you might have insulin active in your body from a previous bolus (this also could help if you already bolused for a meal and simply forgot that you did). It's like it says, “Wait a minute? I just gave you insulin a couple of hours ago and I’m still working here so, can you please not add any more insulin in here to make a correction to your high BG? Thanks.”

The fact that your MiniMed™ pump tracks active insulin is a pretty cool safety feature. If the Bolus Wizard™ calculator recommends that you give a reduced amount of correction insulin or no correction insulin, it’s because you have active insulin remaining from a previous bolus. There’s a term knows as “stacking”. If you have never heard of stacking, it’s no laughing matter. It’s injecting another dose of insulin too soon after a previous dose, resulting in low blood glucose. Active insulin not only allows for more accurate dosing, it helps prevent “stacking” of insulin which could lead to hypoglycemia.

So what happens if you enter your BG readings and carbs into your Bolus Wizard™ and it recommends less than you anticipated? Well, before you send your Bolus Wizard™ off to a math tutor, first have a look on the home screen of your pump, check if you have active insulin on board and take that into account.

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