Method and apparatus for improving lag correction during in vivo measurement of analyte concentration with analyte concentration variability and range data
First Claim
1. A method comprising:
 determining at least one of analyte concentration variability and analyte concentration range;
determining a lag correction value to apply to sensor data representative of analyte concentration measured in interstitial fluid using an analyte measurement system;
adjusting the lag correction value to apply to the sensor data based upon the at least one of the analyte concentration variability and the analyte concentration range; and
computing an analyte concentration level representative of a blood analyte concentration level based on the adjusted lag correction value.
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Abstract
Methods, devices, and systems are provided for correcting lag in measurements of analyte concentration level in interstitial fluid. The invention includes receiving a signal representative of sensor data from an analyte monitoring system related to an analyte level measured over time, computing rates of change of the sensor data for a time period of the sensor data, computing a rate distribution of the rates of change, transforming the rate distribution into a linear arrangement, determining a bestfit line for the transformed rate distribution, computing a slope of the bestfit line; and using the slope of the bestfit line as a representation of a variability of the analyte level to adjust an amount of lag correction applied to the sensor data. Numerous additional features are disclosed.
1117 Citations
21 Claims

1. A method comprising:

determining at least one of analyte concentration variability and analyte concentration range; determining a lag correction value to apply to sensor data representative of analyte concentration measured in interstitial fluid using an analyte measurement system; adjusting the lag correction value to apply to the sensor data based upon the at least one of the analyte concentration variability and the analyte concentration range; and computing an analyte concentration level representative of a blood analyte concentration level based on the adjusted lag correction value.  View Dependent Claims (2, 3)


4. A computerimplemented method, comprising:

defining a scaling factor for lag correction; collecting a moving window of historical analyte sensor data; defining a probability density function of the historical analyte sensor data within the moving window; determining a normalized analyte variability ratio; storing the normalized analyte variability ratio computed at regular intervals; comparing the normalized analyte variability ratio to a predetermined value and a number of prior values; setting a value of the scaling factor based on the probability density function; and computing lag corrected values based on the scaling factor.  View Dependent Claims (5, 6, 7, 8, 9)


10. A system for determining analyte concentration in blood based on analyte concentration measured in interstitial fluid, the system comprising:

a processor; and a memory coupled to the processor, the memory storing processor executable instructions to; define a scaling factor for lag correction; collect a moving window of historical analyte sensor data; define a probability density function of the historical analyte sensor data within the moving window; determine a normalized analyte variability ratio; store the normalized analyte variability ratio computed at regular intervals; compare the normalized analyte variability ratio to a predetermined value and a number of prior values; set a value of the scaling factor based on the probability density function; and compute lag corrected values based on the scaling factor.  View Dependent Claims (11, 12, 13, 14, 15)


16. A computer program product stored on a computerreadable medium comprising executable instructions to:

define a scaling factor for lag correction; collect a moving window of historical analyte sensor data; define a probability density function of the historical analyte sensor data within the moving window; determine a normalized analyte variability ratio; store the normalized analyte variability ratio computed at regular intervals; compare the normalized analyte variability ratio to a predetermined value and a number of prior values; set a value of the scaling factor based on the probability density function; and compute lag corrected values based on the scaling factor.  View Dependent Claims (17, 18, 19, 20, 21)

1 Specification