Page 248 - Glucose Monitoring Devices

252 CHAPTER 12 Modeling the CGM measurement error

sensor engineering. The generic deviations can be approximatedreasonablywell
by a diffusion model. The sensor-specific errors appear to be generally limited
to the order of the ARMA model and the shape of the sensor error distribution.
Thus, both types of errors can be described by a few model parameters and
included in a simulation. A specific type of error is omitted by this methodology:
high-frequency errors (period of 1e15 min) cannot be modeled with our tech-
niques. At this time, no data are available to extract the characteristic of the error
at that fine a sample frequency (we would need reference values every minute in a
large dataset). Nonetheless, the development of a simulated sensor becomes
feasible and became a component of the larger metabolic system simulator devel-
oped at the University of Virginia and the University of Padova. This simulator was
accepted by the Food and Drug Administration for preclinical testing of closed-
loop glucose control strategies. Such in silico testing is now employed by the
Juvenile Diabetes Research Foundation Artificial Pancreas Consortium, provides
insights on the effectiveness of control algorithms during realistic conditions,
and allows the direct transition from in silico testing to clinical trials.

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