How to Use the Bolus Wizard in AndroidAPS
A started guide for the Average Joe
If you’re using, or thinking about using, AndroidAPS for managing your diabetes, you’re about to step into a new level of control over your health. You’ve probably had guidance from your doctor or nurse on how to use a pen or pump. But the Bolus wizard goes beyond what most healthcare providers typically cover.
In this post, we’ll walk through the essentials and share practical tips so you can confidently master the Bolus Wizard. Our aim is to help you feel comfortable with every decision.
If you have any questions or need guidance, reach out to our team at opensource.clinic — let’s make this journey together.
What it does
The Bolus wizard makes your life easier in the following ways:
- Simplifies Math: Most of us hate the complicated diabetes math before meals. The Bolus wizard takes care of that.
- Helps taking into account multiple factors: It can calculate your corrected insulin need based on factors like current highs or lows glucose values, the amount of insulin you have in your body from previous administrations (insuline on board or “IOB”) or remaining carbs after a recent meal.
- Improves stability: Especially when used together with the “Eating Soon” mode (a special mode that makes your body ready for eating food), it’s possible to achieve flat glucose curves after carb rich meals.
- Saves your data: Every calculation can be shared with health care professionals, family members or mentors. If there is a connection to a Nightscout server, the bolus and carb amounts are automatically uploaded and can be monitored live stream or reviewed later.
Basic features
The Bolus wizard has the following basic functionalities.
1. Carbs
In the middle section of the Bolus wizard you can input the amount of carbs that you are about to eat. It’s difficult to exactly estimate the amount of carbs of a meal down to the gram but there are multiple apps that can support in this. Smartphone apps like Snaq and Gluroo use photos from your smartphone to make a fairly reliable estimate of the amount of carbs in your meal. Always have a (digital) kitchen scale in your kitchen to do fast and fully accurate weight assessments of high carb content products like oatmeal, rice and potatoes.
2. Corr
You can use the bottom section “Corr” to correct the amount of insuline thats being administered by your loop. This is often used to create a safety margin in the amount of insulin administered.
Adjustments should be made based on the type of expected carb release in the meal: fast-acting carbs, slow-acting carbs or a mixture (medium releasing meals). To get an idea of meals that lead to a fast, medium or slow release take a look at this ChatGPT conversation (and ask additional questions if needed).
You can use the following protocol to stay on the safe side.
Fast releasing meals (white bread, fruit juices, pastries)
- If you’re under 8 mmol/L, you can use around 70% of the total amount of carbs and let the AndroidAPS correct for the rest if needed. AndroidAPS will do this with super micro boluses, referred to as SMBs. This are small boluses given automatically to correct for high blood sugars.
- If you’re above 8 mmol/L when you start eating, you might opt for a higher percentage of insuline, around 80%, that covers the total amount of carbs.
Medium releasing meals (whole grain bread, quinoa, sweet potatoes)
- You can use 50-70% of the total amount of carbs and let the AndroidAPS correct for the rest with SMBs.
- Use the remaining 30–50% of the carbs as input for eCarbs. Start the eCarbs 60–90minutes into the future and spread out the eCarbs over a time duration of 2 (rice, quinoa) to 6 (pizza, pasta) hours.
Slow releasing meals (brown rice, pizza, pasta)
- Use around 50% of the total amount of carbs as input for carbs in the Bolus wizard.
- Use the other 50% as input for the eCarbs. Spread out the eCarbs over a time period of 2 (rice, quinoa) to 6 (pizza, pasta) hours.
If you are going to sleep, or sit behind a desk for long periods, you might add 10%-20% extra of insuline above the above the mentioned percentages as the insulin will act slower due to not being active in bed. Only do this if you’re glucose levels are on the higher end (> 8 mmol/L).
If you’re about to do an intensive workout within the next 4 hours, take preparatory measures described over here and here, and try to use eCarbs instead of the Bolus wizard as much as possible to prevent hypo’s. You can spread them out over a period of 1–3 hours for fast to medium release meals with carbs or 4–6 hours for slow meals with slow release carbs. Only if really needed, use 10–50% of your carbs as input for the Bolus wizard.
3. BG
In the BG section you can input the current glucose levels. Used rarely and mostly for cases where a fingerstick test is needed (CGM glucose value not available, doubt about CGM measurement reliability or no access to CGM).
Additional options
There are additional options which can be made visible by clicking on the checkbox near the eye icon.
A set of extra checkboxes will appear.
- High or low glucose levels? Tick BG, but only if you’re sure your glucose level will stay the same over the coming 15–45 minutes. If you’re expect a down trend due to physical activity, a correction of a high glucose level can lead to hypos. The same holds for low levels. If you for instance already drank ate a piece of bread 5 minutes ago to correct for a low then leave the checkbox empty or untick it.
- Did you have a recent meal in the last 2–4 hours with FAST carbs? Make sure to tick IOB (insulin-on-board) and leave COB (carbs-on-board) out. The insulin in the body will already have covered most of the fast-acting carbs and can therefore can be subtracted from the amount given now.
- Did you have a recent meal in the last 2–4 hours with SLOW carbs? Tick IOB together COB but only if you expect
- Going up?: Tick 15min trend if you notice your glucose is trending up, you’re currently high, and you expect it to keep rising for the next 30–60 minutes. Keep in mind to only apply 15min trend if you don’t expect the trend to change suddenly due to for instance upcoming physical activity.
Profile Changes
If you’ve adjusted your profile for reasons like stress, illness, or weight changes, the Bolus wizard will use adjusted numbers based on the new profile for the calculation of a bolus. This can lead to under or overdosing if not used carefully.
For example, if you’re used to bolusing 20 units of insulin for a particular meal, the Bolus wizard will indicate 25 units if the profile is 125%. However, you already have an increased basal insulin level so the extra insulin you need for the meal might very well already be covered by that. We therefore advice to use your 100% profile be selecting it in the Profile section shown below because the risk of overdosing is too high.
Be carefull…
While the Bolus wizard offers valuable assistance in managing insulin doses, it’s essential to approach it with caution. Here are some key elements to be mindful of:
- Time Lag in Glucose Sensing: There can be between 5–15 min between the glucose values in your blood and the glucose value that you see on your mobile phone. This is important to consider when determining your insulin dose with the Bolus wizard.
- Potential Calculation Inaccuracies: Although the Wizard strives to provide perfect dosing, factors like the age of your sensor, the age of your cannula/infusion and battery level of your pump can impact its precision. As a result, calculations of the needed amount of insulin may not always, and is actually never, entirely accurate.
Easy methods to improve the accuracy are the routine aspects of self-care: refreshing cannula on time, measuring amount of carbs, eating healthy (foods that don’t lead to large glucose variations) and staying physically active. - Perfectionism: Be careful with aiming for perfectly straight blood sugar lines. It can feel great to see a flat line at 6 mmol/L, but it leaves little room for error. If you’re about to exercise or didn’t eat enough carbs for an intense workout, your blood sugar could crash. Always focus on preventing low blood sugar before worrying about high levels.
For more info:
- How to Think Like a Pancreas — it’s a great resource for anyone managing diabetes.
- The AndroidAPS docs on the Bolus wizard.
- The Facebook group of AndroidAPS or one other open-source diabetes management facebook groups.
- Or feel free to send us a message.
