6.1. Bolus Advisor explained

Common terms

Coefficients

ISF – Insulin Sensitivity Factor
I:C – Insulin to carbohydrates ratio

Active insulin or Insulin On Board (IOB)

IOB = IOBcarb + IOBcorr + RemainingExtendedInsulin – Insulin On Board or Active Insulin
IOBcarb – active insulin from carbohydrates
IOBcorr – active insulin from previous correction
RemainingExtendedInsulin – the remaining amount of the extended bolus

The IOB calculation is based on the curve shown in 9.2 Active insulin topic.

The algorithm to split IOB to IOBcarb and IOBcorr is:

→ IOBcarb = 0
→ IOBcorr = 0

FOR all entries in the last 8 hours DO
    → Calculate *bolusPercent* from the time of the entry to the current time, 
      according to the IOB curve for the selected active insulin duration

    IF entry has carbohydrates THEN
         → carbBolusIOB = min(bolus, carbohydrates/I:C) * bolusPercent
         → corrBolusIOB = bolus * bolusPercent - carbBolusIOB

    IF  entry doesn't have carbohydrates THEN
         → carbBolusIOB = 0
         → corrBolusIOB = bolus * bolusPercent

    → extendedInsulinIOB = 0

    IF  entry has extended insulin THEN
        → Calculate *extendedInsulinIOB* according its duration and current time

    → IOBcarb = IOBcarb + carbBolusIOB + extendedInsulinIOB
    → IOBcorr = IOBcorr + corrBolusIOB
END

→ IOB = IOBcarb + IOBcorr

!If extended bolus is applied then the remaining amount is added to the IOBcarb and respectively to the total IOB for the bolus calculation. That way the future insulin, which will be added during the extended bolus duration, will be included in the correction in order to avoid overdosing.
 
The remaining extended insulin amount is NOT added when Diabetes:M is displaying the Active insulin on the Home screen and in the Bolus Advisor result area so the Active insulin value in those screens is the real IOB.