Explaining active insulin

bolus wizard

True or false? Active insulin is a type of insulin that is out-going, heavily involved in sports and enjoys outdoor activities. False, it's actually an interesting and really important insulin pump feature included in the Bolus Wizard feature of our insulin pumps! 

If you use the Bolus Wizard and you're still not sure what active insulin is or how it's calculated, this blog is for you. Have you ever noticed that you tried to bolus insulin through the Bolus Wizard, and it changed the estimated amount of insulin you need? This is because of "active insulin." 

Let's start off with a word problem. What is the estimated total amount of insulin that will be delivered by your pump if you entered in a blood glucose of 200 with 60 grams of carbs with background settings of a 1:10 carb ratio, a 100 BG target, and an insulin sensitivity of 50? 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 of insulin instead of 8. As you know, this can make a big difference in your blood glucose. Those 2 units from your last bolus - that's active insulin. This feature is able to change bolus recommendations in cases like this one, when you might have insulin active in your system 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 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 known as "stacking" (and I'm not talking pancakes here). If you have ever 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 sugar. 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 in your BG readings and carbs into you Bolus Wizard and it recommends less than you anticipated? Well, before you send your Bolus Wizard off to a math tutor, go into your status screen, check to see if you have active insulin on board, and take that into account.

IMPORTANT SAFETY INFORMATION

- Medtronic Diabetes insulin infusion pumps, continuous glucose monitoring systems and associated components are limited to sale by or on the order of a physician and should only be used under the direction of a healthcare professional familiar with the risks associated with the use of these systems. - Successful operation of the insulin infusion pumps and/or continuous glucose monitoring systems requires adequate vision and hearing to recognize alerts and alarms.

Medtronic Diabetes Insulin Infusion Pumps

- Insulin pump therapy is not recommended for individuals who are unable or unwilling to perform a minimum of four blood glucose tests per day. - Insulin pumps use rapid-acting insulin. If your insulin delivery is interrupted for any reason, you must be prepared to replace the missed insulin immediately.

Medtronic Diabetes Continuous Glucose Monitoring (CGM) Systems

- The information provided by CGM systems is intended to supplement, not replace, blood glucose information obtained using a home glucose meter. A confirmatory fingerstick is required prior to treatment. - Insertion of a glucose sensor may cause bleeding or irritation at the insertion site. Consult a physician immediately if you experience significant pain or if you suspect that the site is infected. For more information, please visit MedtronicDiabetes.com/isi.

 

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Saved as a favorite, I really like your site!

Glad to hear you’re finding the LOOP blog helpful! Please let us know what other content you’d like to see!

Submitted by Bill (not verified) on

In reply to by naomi.kingery@…

Hi Naomi,
Can you provide more information on how the active insulin is calculated? I don't mean to be blunt but the explanation above is way too simplistic.
I'm looking for either the formula or distribution.
Also, isn't everybody's body different? Aren't there several factors that significantly influence absorption and duration? If yes, why does Medtronic have a one size fits all formula?
Finally, isn't active insulin really meaningless with the corresponding active carbohydrate? If yes, why doesn't Metronic add a feature for active carbohydrate?
I'm just a patient.

Submitted by Karrie Hawbaker (not verified) on

In reply to by Bill (not verified)

Hi Bill. Because of the detail needed to answers your questions, it’s best to contact our 24-Hour HelpLine at 800.646.4633 option #1. They’d be happy to help with any questions you may have.

Submitted by bill (not verified) on

In reply to by Karrie Hawbaker (not verified)

Hi Karrie,
Isn't the amount of active insulin dependent on several factors such exercise, stress, body weight, and a whole host of other factors?
Is it wise to trust Metronics calculation as it does not take into account all these factors that affect both insulin absorption and sensitivity?
To your answer above, I'm pretty confident the 24-hour help line is just minor trouble shooting and not there for product questions (my question would be beyond their scope). My experience has been the reps on the line can't answer pressing issues like flow block alarms or functionality of alarms.

Submitted by Karrie Hawbaker (not verified) on

In reply to by bill (not verified)

Thanks for reaching out, Bill. This is a good question and we'd like to look into this more with you. Please send your contact info to dhelp@medtronic.com and we'll get you connected with someone who can help.

Submitted by Patient with 2… (not verified) on

In reply to by Bill (not verified)

Great question!

Submitted by Kennith pulley (not verified) on

In reply to by naomi.kingery@…

I have a question can I change my quickset infusion set while there is active insulin on board or do I have to wait until it says 0.0 units before I change my set ran out in my pump just don't want to make a mistake

Submitted by Nicole (not verified) on

In reply to by Kennith pulley (not verified)

Hi there, Kennith. Your infusion set can be changed while there is active insulin on board. Active insulin on board reflects how much insulin is remaining in the body from a previous bolus (or boluses) that will continue to lower glucose. Please let us know if you have any other questions.

Submitted by Eleni (not verified) on

In reply to by Commenter (not verified)

Hello! Congtrats on the good job you do through this blog. I find that the best advantage of the pump is active insulin calculation. I have a question though. What happens when your bg is within target limits and yet you have a good amount of active insulin left? When you bolus for carbs, it does not extract that amount from the total and that makes me worried...

Submitted by naomi.kingery@… on

In reply to by Eleni (not verified)

Thanks so much, Eleni! I’m so glad you’re enjoying The LOOP blog. We are committed to delivering more of the content that our community wants to see, so let us know what you’d like to see more of, and you can keep up with our latest posts by subscribing here: http://feeds.feedburner.com/loop-blog.

The active insulin time setting in your pump determines any active insulin still in your body from your prior boluses, so it calculates the amount of active insulin and subtracts the active amount before estimating a bolus. For example, if you recently had a snack and then checked your glucose before eating your next meal and before your previous insulin dose has had its full effect, your pump accounts for the insulin you’ve already taken to ensure that you get the correct dose. You may find this article on the bolus wizard helpful, too: http://www.loop-blog.com/4-features-of-the-bolus-wizard/. Please let me know if you have any other questions.

Submitted by Vlado (not verified) on

In reply to by Eleni (not verified)

Eleni,when your bg is in target limits and you have any active insulin it is supposed to mean that you have the same amount of food on board yet to be absorbed from your stomach and your pump has no privilege to extract it from your next bolus for another meal.

Submitted by Eleni (not verified) on

In reply to by Vlado (not verified)

Thank you for your replies. I have a 3 yr old son with DT1 for 12 months now. We have the pump for 3 months now. The other day he had 113 BG and 0.400 units active insulin left about 90mins after his breakfast. I had to give him half a toast (15gr carbs) with no bolus to compensate... However i find that after a fatty meal any excess of active insulin is effectively used up.
Anyway, thank you again for your time.

Submitted by Debbie (not verified) on

In reply to by Commenter (not verified)

This was an excellent information. Have looked for years for answer now have found my answer, didn't know site would be informative. Thank you!!

Submitted by naomi.kingery@… on

In reply to by Debbie (not verified)

Debbie, I’m so happy you found this article on active insulin helpful! We try to meet the needs of our community with different posts focused on health and wellness, education and information, lifestyle, and innovation that benefit the entire diabetes community.

when you set the hours on active insulin,does that mean that it will take that many hours to get all the insulinyou have taken through your body. my time was 6 hours but i cut to 3, am i doing right. mybs swings all the time.

Hennies, the active insulin time setting lets the pump know which active insulin time to use in calculating the amount of active insulin to subtract before estimating a bolus. The default time of active insulin is six hours, but your healthcare professional should determine the active insulin time that works best for you. I’ll have a member of my team reach out to you to try and help with additional questions.

Submitted by sherri Patten (not verified) on

In reply to by Commenter (not verified)

I too am wondering if my active insulin is 6hrs. Does that mean insulin lasts for 6 hrs? So do I get more insulin with it set on 6-hrs or if changed to 3-would I get more insulin?

Submitted by naomi.kingery@… on

In reply to by sherri Patten (not verified)

Sherri, the active insulin time setting lets the pump know which active insulin time to use in calculating the amount of active insulin to subtract before estimating a bolus. Your MiniMed insulin pump is shipped from the factory with an active insulin time setting of six hours, which most closely matches the published scientific data. The active insulin time setting can be adjusted in the Bolus Wizard menu in one-hour increments from two to eight hours. Your healthcare professional should determine the active insulin time that is best for you. I’ll have a member of my team reach out to you to help explain further, and answer any other questions you may have.

Submitted by jorie (not verified) on

In reply to by Commenter (not verified)

I have been running very high BG for 2-3 weeks. Yesterday my doctor made a couple of minor adjustments with the basal rate. However, I think my problem is the active insulin time. I calculate the carb intake with a meal (which are both very small amounts) and two hours later when I recheck BG, it is very high. When I try to bolus, it does not offer me one as there is a still most of insulin remaining from the pre-meal previous setting. My active setting is set at 8 hrs.

Submitted by LOOP Blog Editorial on

In reply to by jorie (not verified)

Jorie, I’m sorry to hear that. I encourage you to continue to work with your doctor as they're in the best posotion to help with your individual needs. If you have any questions related to a Medtronic device, let me know and I can connect you with someone.

Submitted by Cathey Challis (not verified) on

In reply to by Commenter (not verified)

I've been running scared over the last week. I cannot get my blood sugar much under 250mg. I am allowing my mind to throw doubt darts at me when it comes to active insulin. Did it mean that it was already added at last, or did it mean insulin not introduced and waiting according to rate. Thanks for the reassertion. Very helpful.

Submitted by Karrie Hawbaker (not verified) on

In reply to by Cathey Challis (not verified)

Hi Cathey, active insulin is the amount of insulin that is still active in your body from previous boluses and that could continue to lower your BG (blood glucose). The pump considers your active insulin setting in determining any active insulin still in your body from your prior boluses. If this doesn't help answer your question, please reach out to our 24 HelpLine to discuss further. The team can be reached at 800-646-4633, option 1.

Submitted by Fran Pritchert (not verified) on

In reply to by Commenter (not verified)

Naomi, thank you for your blog. Now I truly understand Active Insulin

Submitted by hennies railey (not verified) on

In reply to by Commenter (not verified)

Hi, it's me again, I just checked my bs two hours after my supper, my bs was 119 and had 9,5 active insulin. I ate a 35 carb apple and gave myself 4 units of insulin. Right or wrong, scared of running bs up.I had my active insulin set for 3 hours,but changed it today to 5 hours,pump was factory to 6. Asked my doctor for a number but did not get an answer. Thanks

Submitted by Karrie Hawbaker (not verified) on

In reply to by hennies railey (not verified)

Hennies, thanks for reaching out. While I recommend working with your healthcare team, our 24-Hour HelpLine may be able to help. Please give them a call at 800.646.4633, option 1. They are available 24 hours a day, 7 days a week.

Submitted by Morteza (not verified) on

In reply to by Commenter (not verified)

Hi. Thanks for pay attention to comfort sike childeren but we can't having this equipment for our daughter bicuse that device is so expensive for us

Submitted by Karrie Hawbaker (not verified) on

In reply to by Morteza (not verified)

We are proud to be a partner for those with diabetes, Morteza! We know diabetes management in any form can be expensive, but we have programs that may be able to help. From financial assistance to payment plans for as little as $1 a day, we're here to help. Both programs have eligibility requirements, but if you'd like to learn more, give us a call at 800.646.4633, option 3, to speak with a device specialist.

Submitted by Gayle C. Kirma (not verified) on

In reply to by Commenter (not verified)

Hi Karrie, Is Active Insulin Time the same as Duration of Insulin Action? I'm reading different articles and need clarification. Thank you!

Submitted by Karrie Hawbaker (not verified) on

In reply to by Gayle C. Kirma (not verified)

Gayle, this is a great question and I had to do some digging to find out more. Based on an internet search, these appear to have the same meaning. We do still recommend checking in with your healthcare team for specifics. Good luck with your research.

Submitted by sudhakar kandikatla (not verified) on

In reply to by Commenter (not verified)

From above I understand the active insulin is a safety feature for bolus wizard to protect you from over calculation of bolus insulin for the carb intake you entered.

Submitted by Bruno Caetano (not verified) on

In reply to by Commenter (not verified)

When I use the Bolus wizard with a glicemia of, let`s say, 200, the bolus calculation deducts, as you said, the active insulin. However, when glicemia is under 100, the active insulin is not deducted from the bolus, increasing the hyperglicemia risk.
At school my son eats at 11:00 and at 13:00. He has 0,2 active insulin at 13:00. His FSI is 200. Last week, for a food Bolus of 1, and a glicemia of 140, a Total Bolus of 1 was advised. However, the next day, with G at 73. A total Bolus of 0,865 was computed (1 for de food and -0,135 for correction). In my opinion, the 0,2 of active insulin should have been deducted, resulting in a toal bolus of 0,665. Result: he took the advised 0,875 bolus and he had an hiperglicemia afterwards. Could you comment on this situation?

Submitted by Nicole (not verified) on

In reply to by Bruno Caetano (not verified)

Bruno, this would be a good conversation to have with our 24-Hour Technical Support team. If you're in the US, please give our team a call at 800.646.4633 option #3. If you're outside the US, you can find your local contacts here: http://bit.ly/1ce3pEc

Submitted by Bruno Caetano (not verified) on

In reply to by Commenter (not verified)

Actually I read the instructions book and it confirms that for low levels of glycose the active insulin will deliberatly not be deducted in the Bolus Wizard computation. WHY IS THAT? For a glycose of 200 the active insulin is deducted because we are afraid of a hypoglicemia. However for 70, when we are at the brink of hypoglicemia and with active insulin on your body, the Bolus Wizard will "forget" the active insulin. This is absolutely counterintuitive and is extremely dangerous. Why is this done this way? My son avoided a huge hipoglicemia caused by this situation, because he was extremely aware of its glycose values.

Submitted by Carol (not verified) on

In reply to by Commenter (not verified)

I just got my pump 3 days ago, and since I've never carb counted, she has me estimating like I've always done, and bolus. In a month, I'll start carb counting and be trained for that. My question is, my glucose can be up around 180-200, I still have active insulin in me, so why hasn't it lowered my glucose after almost 3 hours? It was doing great keeping me regulated, now this. Do I just have keep bolusing more, a little at a time?

Submitted by Nicole (not verified) on

In reply to by Carol (not verified)

Carol, you may benefit from a review of your settings with your healthcare provider. Of course, or 24-Hour Technical Support team is always available to make sure everything is working as designed and can be reached at 800.646.4633 option #1.


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