More and more devices exist on the market with technologies that go towards the insulin pump resembling an artificial pancreas, letting the user allow the insulin pump to automatically stop and resume insulin delivery. All insulin delivery will stop when the blood glucose level is low or is predicted to be low within a certain time, and resume once the blood glucose level has gone up.
This function has different names depending on manufacturer. In diasend® we have chosen to use the terms Low Glucose Suspend (LGS) and Predicted Low Glucose Suspend (PLGS). For the Tandem T:Slim X2 it is called Basal-IQ technology.
The difference between LGS and PLGS.
- LGS – Low Glucose Suspend. Based on CGM data, the pump suspends insulin delivery when the blood glucose level is low, and resumes delivery once the blood glucose level has gone up.
- PLGS – Predictive Low Glucose Suspend. Based on CGM data and algorithms in the pump, the pump suspends insulin delivery when it is calculated that the blood glucose level will be low within a certain time, and resumes delivery when the blood glucose level rises.
What constitutes as “low” differs depending on device. It can be preset and unchangeable, or individual.
A pump with LGS/PLGS functions is always connected to a CGM, as it uses the CGM data as input to the algorithms to manage the automated insulin suspension and resumption.
LGS/PLGS is visible under these tabs:
- Insulin > Day-by-day
- Comparison > Day-by-day
Under Events, it is possible to see:
- PLGS – Time when PLGS kicks in
- LGS – Time when LGS kicks in
- Resumed – Time when basal insulins kick in again after an LGS/PLGS event
On the right side of the graphs, next to the tables with Basal and Bolus events, LGS/PLGS events are available as well. It is possible to see :
- Total time suspended each day (rounded to full minutes)
- Time (of the day) of each suspend event
- Duration of each suspend event (rounded to full minutes)
Hovering over the 
sign displays the full name of LGS/PLGS. This is the same in all languages and does not translate.
If a Tandem t:slim X2 is uploaded while LGS/PLGS is active, then that last, ongoing period of LGS/PLGS will not be seen. What will be visible is the basal rate going down to zero as it is the last event that the pump has reported to us.
Some examples of what the graphs can look like, in combination with other events:
Regular basal (programmed basal) goes all throughout the day (except when LGS/PLGS kicks in). Basal curve stays blue when LGS/PLGS is activated (before, during and after).
Temporary basal at 10:00 makes the curve red. Stays red when LGS/PLGS kicks in (before and during). When regular basal resumes after LGS/PLGS event, curve is blue (after) since the programmed end time for the temporary basal has passed. The same thing happens again before 11:00 (red before and during, blue after).
Temporary basal rate makes the curve red. Both when LGS/PLGS kicks in and when insulin delivery resumes. Basal rate is red since the temporary basal has been programmed for that period of time.
In this example an extended bolus is terminated when LGS/PLGS kicks in.
Note: All insulin delivery is stopped when LGS/PLGS kicks in.