Why can’t I see my Insulin on Board (IOB) Time Remaining when using Control-IQ technology?
The Insulin On Board (IOB) Time Remaining indicates how long the total units of insulin from food and correction boluses will be active in the body. IOB is tracked slightly differently when Control-IQ technology is turned on (see below). Time remaining is not displayed when Control-IQ technology is turned on because the technology can adjust insulin delivery every 5 minutes if needed. The IOB units will always be displayed on the Home and Lock screens.
How IOB is tracked when Control-IQ is turned on
If you have had a previous version of the t:slim X2 pump, you may recall that Insulin on Board (IOB) only included insulin from boluses, not basal insulin.
If you have Control-IQ technology turned on, your pump remembers and tracks all basal delivered above and below the programmed Basal Rate, in addition to all bolus insulin delivered.
In other words, when Control-IQ technology tells the pump to deliver more insulin compared to personal profile settings, IOB increases. When Control-IQ technology tells the pump to deliver less (or no) insulin compared to your personal profile settings, IOB is reduced.
Please note: If Control-IQ decreases basal insulin below your programmed Basal Rate, it will reduce your IOB. If your IOB was already low, this could mean that the pump considers your IOB to be a negative value. During this time, displayed IOB will still show as “0”. If you deliver a bolus during this time, you may not see the full bolus amount reflected in the IOB.
Not to worry, the pump is still working as expected. You can check the pump’s Current Status or History screens to verify bolus delivery.
Here are 3 different scenarios where the pump screen might display 0 units of IOB:
1. Control-IQ reduced basal delivery, so IOB remembered by the pump was negative:
| Pump Home Screen | IOB Displayed | IOB Remembered by Pump |
|
Before Bolus |
0 units | -1 units |
|
After 5-unit Bolus is delivered |
4 units | 4 units |
2. IOB was still negative after bolus:
| Pump Home Screen | IOB Displayed | IOB Remembered by Pump |
|
Before Bolus |
0 units | -6 units |
|
After 5-unit Bolus is delivered |
0 units | -1 units |
3. IOB was 0 before bolus was delivered:
| Pump Home Screen | IOB Displayed | IOB Remembered by Pump |
| Before Bolus |
0 units | 0 units |
|
After 5-unit Bolus is delivered |
5 units | 5 units |
Always refer to the User Guide for important safety information and detailed step-by-step instructions on how to understand how IOB works on your t:slim X2 pump with Control-IQ technology. Please consult the applicable user guide below and refer to the table of contents.