Methods of lag-compensation for analyte measurements, and devices related thereto
Inventors
Budiman, Erwin S. • Li, David L.
Assignees
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Publication Number
US-12471850-B2
Publication Date
2025-11-18
Expiration Date
Abstract
Methods comprising applying a first analyte point measurement filter comprising: receiving, from an in vivo analyte sensor, at least a first, second, and third uncompensated analyte measurement at a first, second and third reference time; determining a first scaled rate-of-change by multiplying a first weighting coefficient and a first rate-of-change, the first rate-of-change computed between the first uncompensated analyte measurement at the first initial reference time to the second uncompensated analyte measurement at the first prior reference time; determining a second scaled rate-of-change by multiplying a second weighting coefficient and a second rate-of-change, the second rate-of-change computed between the first uncompensated analyte measurement at the first initial reference time to the third uncompensated analyte measurement at the second prior reference time; and calculating a first filter lag-compensated point measurement based on the sum of the first uncompensated analyte measurement, the first scaled rate-of-change, and the second scaled rate-of-change.
Core Innovation
The invention addresses determining a level of an analyte in a bodily fluid with an analyte monitoring system that includes an in vivo analyte sensor in contact with interstitial fluid and an analyte monitoring device that monitors analyte over a period of time. The problem addressed is that analyte measurements sensed in interstitial fluid have a lag relative to measurements sensed in blood, so the method compensates for this lag when determining an estimated blood analyte level.
The core approach determines a combination of time delays by defining a search space, evaluating candidate combinations of time delays within the search space based on an evaluation function, and selecting first and second time delays from the candidate combinations based on the evaluation function. The selected time delays correspond to prior reference times used to sense uncompensated analyte measurements at prior time points relative to a first initial reference time.
After receiving multiple uncompensated analyte measurements sensed in interstitial fluid at the first initial reference time and at prior reference times, the analyte monitoring device applies a point measurement filter that determines scaled rate-of-change terms by multiplying weighting coefficients by rates-of-change computed between the uncompensated measurements. The device calculates a filter lag-compensated point measurement based on the uncompensated analyte measurement and the scaled rate-of-change terms, and then determines an estimated blood analyte level at the first initial reference time using this lag-compensated point measurement, compensating for the interstitial-to-blood lag.
The system and method further include displaying a representation of the estimated blood analyte level at the first initial reference time. The invention is documented as applicable to glucose monitoring with an in vivo sensor in contact with interstitial fluid and a glucose monitoring device, where the same time-delay determination and lag-compensated point measurement filtering is used to determine and display an estimated blood glucose level.
Claims Coverage
The partial content provides three independent claim sets (analyte monitoring method, analyte monitoring system, and glucose monitoring method). Each includes determining a combination of time delays using a search space and evaluation function, sensing multiple uncompensated interstitial-fluid measurements associated with an interstitial-to-blood lag, and applying a filter that uses weighted, scaled rate-of-change terms to compute a filter lag-compensated point measurement used to estimate a blood analyte level that is displayed.
Time-delay combination selection via search and evaluation function
Determining, by one or more processors, a combination of time delays including a first time delay and a second time delay by defining a search space; evaluating a plurality of candidate combination of time delays within the search space based on an evaluation function; and selecting, based on the evaluation function, the first time delay and the second time delay for the combination of time delays.
Interstitial-fluid uncompensated measurements associated with interstitial-to-blood lag
Sensing, by the in vivo analyte sensor in contact with interstitial fluid, a first uncompensated analyte measurement, a second uncompensated analyte measurement, and a third uncompensated analyte measurement, where the first uncompensated analyte measurement is associated with a lag corresponding to analyte measurements sensed in the interstitial fluid relative to measurements sensed in blood, and where the prior time points correspond to first prior reference time and second prior reference time corresponding to the first time delay and second time delay.
Filter lag-compensated point measurement using weighted, scaled rates-of-change
Applying a first analyte point measurement filter by determining a first scaled rate-of-change by multiplying a first weighting coefficient and a first rate-of-change (computed between the first uncompensated analyte measurement at the first initial reference time to the second uncompensated analyte measurement at the first prior reference time), determining a second scaled rate-of-change by multiplying a second weighting coefficient and a second rate-of-change (computed between the first uncompensated analyte measurement at the first initial reference time to the third uncompensated analyte measurement at the second prior reference time), and calculating a first filter lag-compensated point measurement based on the first uncompensated analyte measurement, the first scaled rate-of-change, and the second scaled rate-of-change.
Estimated blood analyte level compensated for interstitial-to-blood lag and displayed representation
Determining an estimated blood analyte level at the first initial reference time using the first filter lag-compensated point measurement calculated based on the uncompensated analyte measurement sensed in interstitial fluid, where the estimated blood analyte level compensates for the lag corresponding to analyte measurements sensed in interstitial fluid relative to measurements sensed in blood, and displaying a representation of the estimated blood analyte level at the first initial reference time.
System architecture with processor, transmitter, receiver, and memories configured with filtering instructions
Providing an analyte monitoring system comprising an in vivo analyte sensor positioned beneath a skin surface and in contact with interstitial fluid coupled to a data processing unit, and an analyte monitoring device comprising a receiver, and memory and processors configured to cause operations including receiving measurements from the in vivo analyte sensor, applying the first analyte point measurement filter using weighting coefficients and rates-of-change, determining the estimated blood analyte level compensated for the lag, and displaying a representation of the estimated blood analyte level.
Glucose-specific lag-compensated blood glucose estimation from interstitial measurements
Determining, by one or more processors of a glucose monitoring system, a combination of time delays with a first and second time delay selected based on defining a search space, evaluating candidate combinations based on an evaluation function, and selecting time delays based on the evaluation function; sensing interstitial-fluid uncompensated glucose measurements associated with a lag relative to measurements sensed in blood at a first initial reference time and prior time points corresponding to the first time delay and second time delay; applying a first glucose point measurement filter that determines first and second scaled rates-of-change by multiplying weighting coefficients by rates-of-change computed between the initial and prior glucose measurements; calculating a first filter lag-compensated point measurement based on the first uncompensated glucose measurement and the scaled rate-of-change terms; determining an estimated blood glucose level at the first initial reference time that compensates for the interstitial-to-blood lag; and displaying a representation of the estimated blood glucose level at the first initial reference time.
Across the independent claims, the inventive focus is on selecting a combination of first and second time delays using a search space and evaluation function, using multiple interstitial-fluid uncompensated measurements associated with an interstitial-to-blood lag, and applying a point measurement filter that computes weighted, scaled rate-of-change terms to form a filter lag-compensated point measurement. This lag-compensated point measurement is then used to determine an estimated blood analyte level (or estimated blood glucose level) at a reference time, and the resulting estimated level is displayed.
Stated Advantages
Compensates for the lag corresponding to analyte measurements sensed in interstitial fluid relative to measurements sensed in blood.
Documented Applications
Lag-compensation for monitoring an analyte level where the in vivo sensor senses uncompensated analyte measurements in interstitial fluid, including estimating and displaying an estimated blood analyte level.
Glucose monitoring that estimates and displays an estimated blood glucose level based on glucose measurements sensed in interstitial fluid using selected time delays and a lag-compensated point measurement filter.
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