How to Use the Bolus wizard in AndroidAPS
A simple starters guide
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.
In this post we’ll walk through the essentials and share practical tips so you can confidently start to master the Bolus Wizard.
If you have any questions or need guidance, feel free to reach out to our team at Opensource.clinic.
What it does
The Bolus wizard makes your life easier in the following ways:
- Simplifies Math: The Bolus wizard takes care of the nitty gritty of the calculations 😅.
- Helps taking into account multiple factors: It can calculate your corrected insulin need based on factors like current highs or lows , 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 impressive flat glucose curves after carb rich meals.
- Saves your data: If connected to a Nightscout server, the bolus and carbohydrate amounts are automatically uploaded. This data can then be monitored in real-time or reviewed later by you or anyone you choose to share it with.
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. There is also ChatCGM, an app that directly sends your glucose values to Nightscout or AndroidAPS. It works by sending your data to the app via a telegram conversation. Even if you use the latest smartphone apps to reduce the stress of counting carbs, always have a (digital) kitchen scale in your kitchen to do fast, reliable and accurate carb assessments when you’re preparing your meals.
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 in a safe range, let’s say 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.
Physical inactivity
If you are going to watch a movie 🍿 or sit behind a desk 🧑💻 for a long period of time, you might want to add 10%-20% extra of insuline above the above the mentioned percentages and substract that from the eCarbs. The insulin will act slower due to inactivity and there will be a lower risk of hypo’s.
Workouts
If you’re about to do an intensive workout within the next 4–6 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 in edge cases, for instance large meals with total carb content above 60–90 grams, use 10–50% of your eaten 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.
Some extra checkboxes will pop up, and they can be a bit tricky to figure out 😇
When to use BG checkbox?
Tick the BG box only if you’re confident your glucose levels will stay steady for the next 15–45 minutes. If you’re expecting a drop due to exercise, correcting a high glucose level might cause a hypo.
Same goes for when your glucose is low. For example, if you’ve already eaten something to fix a low and you’re about to eat again, leave the BG checkbox unticked. Otherwise, you might end up with less insulin than you actually need.
You can also use this box if you see your pump or patch isn’t working properly and you need to correct a high due to insulin that was not given but AndroidAPS think it has been given 🫤. In these cases, tick the BG box, but don’t add anything else.
When to use 15min trend checkbox?
Tick the 15-minute trend box if you notice your glucose is rising and you’re already high. If you think the trend will keep going up for another 30–60 minutes. The same rule applies if your glucose is going down, and you expect that trend to continue. Just make sure the trend won’t suddenly change (like if you’re about to exercise 🚴🏋️♀️).
When to use COB checkbox?
Tick the COB (Carbs-on-Board) box if you’ve eaten carbs recently, but they aren’t fully covered by your current insulin. For example:
- If you gave less insulin because you planned to exercise but then canceled the workout and need to correct for those carbs.
- Or, if you took insulin but had a technical issue (like your pump or phone dying 👺) and the bolus got interrupted and only a partial bolus has been given by AndroidAPS.
Ticking the COB box will automatically check the IOB (Insulin-on-Board) box as a safety measure.
When to use IOB checkbox?
Did you eat a meal with fast carbs 2–4 hours ago? Always tick the IOB box and leave COB unticked. The insulin you’ve already given will still be active, so you can subtract that from the amount you need to give now.
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 👍🦺.
Always stay on the safe side
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.
- Improve accuracy: 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 hypos before worrying about hypers. 👍
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.
- Opensource.clinic
