Insulin Pump Accuracy

When given a blood glucose reading, insulin pumps reduce the insulin to be delivered by the amount of Active Insulin, or Insulin on Board (IOB).

To calculate the Active Insulin, you must know the patient’s Active Insulin Time, the time(s) of prior dose(s), and the dose amount(s).

Active Insulin can be estimated :

1. using a linear (straight line) ramp-down function. Poor accuracy, especially at the first 20% and last 20% of time period
2. using a pre-calculated table of discrete values with hourly or half-hourly intervals. Reasonably accurate, except at the start and end of the interval. Often found on devices with power constraints e.g. insulin pumps, BG meters and naive iPhone Apps.
3. directly from the insulin-action, algorithmically. Highly accurate, but complex to compute.

Insulin Pumps and BG meters are necessarily limited by battery power, small CPUs, integer-only arithmetic and small amounts of memory.

By contrast, Jade Diabetes runs on a server farm with copious memory, power and CPU computational ability and floating-point arithmetic. Jade Diabetes is able to track even tiny insulin amounts that are still present even after the usual ‘Active Insulin Time’ has expired, leading to better detection of insulin stacking and improved hypo avoidance.