How Continuous Glucose Monitors Estimate Blood Sugar Levels Accurately
This patent describes a method for accurately estimating blood glucose levels by accounting for the natural delay in glucose moving between interstitial fluid and blood, using sensor data and its rate of change.
Original patent title: “Method and/or system for multicompartment analyte monitoring”
This patent describes a method for accurately estimating blood glucose levels by accounting for the natural delay in glucose moving between interstitial fluid and blood, using sensor data and its rate of change. Granted to Medtronic Minimed in 2014 with 25 claims and 9 forward citations, and it is expected to expire in 2031.
Coverage
What does this patent actually cover?
The patent describes a system and method (ClaimclaimA numbered sentence at the end of a patent that legally defines what the inventor owns. The most important section.Read more → 1, 13) for monitoring a substance, called an "analyte," in the body. It specifically focuses on estimating the analyte's concentration in a "first physiological compartment" (like blood plasma, Claim 2) by taking measurements from a "second physiological compartment" (like interstitial fluid, Claim 2). The system "models a latency" (a delay) in how the analyte moves between these two compartments and then "compensates for the latency" when calculating the final estimate. For example, if a continuous glucose monitor (CGM) measures glucose in the interstitial fluid, a processor predicts the blood glucose level, even though there's a natural time lag for glucose to move. This compensation uses not just the current sensor reading, but also the "estimated rate of change" of that sensor signal (Claim 1) to improve accuracy.
The gap
What does this patent NOT cover?
- Does not cover systems that measure analyte levels directly in the first physiological compartment (e.g., a finger-prick blood glucose meter).
- Does not cover methods that estimate analyte concentration without accounting for the latency between two compartments.
- Does not cover systems that only use a single measurement value without considering the rate of change of the sensor signal for latency modeling.
- Does not cover methods where the "first physiological compartment" is not blood plasma or the "second physiological compartment" is not interstitial fluid, if glucose is the analyte (ClaimclaimA numbered sentence at the end of a patent that legally defines what the inventor owns. The most important section.Read more → 2 specifies this common scenario).
These exclusions are unique to PatentBrief — derived from the actual claim language, not patent-office boilerplate.
Key facts
What made this novel
The key innovation is recognizing and mathematically compensating for the time delay (latency) in how an analyte, like glucose, moves between different body fluids. By using the *rate of change* of the sensor signal, the system can better predict future or current blood glucose levels, even when the interstitial fluid reading lags behind.
The Patent Drawing
Schematic visualization of the patent's claim structure. Hand-drawn diagrams in progress for each landmark patent.
Where you've seen this
Real-world examples
Medtronic Guardian Connect CGM
Dexcom G-series CGMs
Abbott FreeStyle Libre
Most modern continuous glucose monitoring (CGM) systems
Why it matters
The bigger picture
This technology is fundamental to continuous glucose monitoring (CGM) devices, which are critical for managing diabetes. By accurately estimating blood glucose from interstitial fluid, it allows people with diabetes to track their glucose trends in real-time without frequent finger-prick tests. This improves daily management, helps prevent dangerous high or low blood sugar events, and informs insulin dosing decisions.
Filed
October 26, 2011
Granted
November 11, 2014
Market context
Who's building on this
Companies in this space
Medtronic Minimed, the original assigneeassigneeThe entity that owns the patent — usually the inventor's employer or a company.Read more →, continues to be a major player in continuous glucose monitoring (CGM) systems. Other leading companies like Dexcom and Abbott also develop and refine technologies for accurate glucose estimation, building on similar principles of physiological modeling and signal processing. The field is highly competitive, with ongoing innovation in sensor accuracy and predictive algorithms.
Market impact
This patent's underlying principles contributed to the widespread adoption and accuracy improvements of continuous glucose monitors. By enabling more reliable real-time glucose data, it has significantly improved diabetes management, reducing the burden of frequent finger-prick tests and empowering users to make better health decisions. It helped solidify the market for non-invasive or minimally-invasive glucose monitoring solutions.
Claim 1 — Plain English
What this patent covers
The patent describes a system and method (Claim 1, 13) for monitoring a substance, called an "analyte," in the body. It specifically focuses on estimating the analyte's concentration in a "first physiological compartment" (like blood plasma, Claim 2) by taking measurements from a "second physiological compartment" (like interstitial fluid, Claim 2). The system "models a latency" (a delay) in how the analyte moves between these two compartments and then "compensates for the latency" when calculating the final estimate. For example, if a continuous glucose monitor (CGM) measures glucose in the interstitial fluid, a processor predicts the blood glucose level, even though there's a natural time lag for glucose to move. This compensation uses not just the current sensor reading, but also the "estimated rate of change" of that sensor signal (Claim 1) to improve accuracy.
The clever bit
The key innovation is recognizing and mathematically compensating for the time delay (latency) in how an analyte, like glucose, moves between different body fluids. By using the *rate of change* of the sensor signal, the system can better predict future or current blood glucose levels, even when the interstitial fluid reading lags behind.
What it does not cover
- Does not cover systems that measure analyte levels directly in the first physiological compartment (e.g., a finger-prick blood glucose meter).
- Does not cover methods that estimate analyte concentration without accounting for the latency between two compartments.
- Does not cover systems that only use a single measurement value without considering the rate of change of the sensor signal for latency modeling.
- Does not cover methods where the "first physiological compartment" is not blood plasma or the "second physiological compartment" is not interstitial fluid, if glucose is the analyte (Claim 2 specifies this common scenario).
Patent timeline
Application submitted to the patent office
Application published, typically 18 months after filing
Patent officially issued
Patent enters public domain
PatentBrief Score
Impact Score
Strong
Citation count
20/40
Early citations
Claim breadth
17/20
Very broad protection
Recency
5/20
Granted 10–20 years ago
Assignee scale
20/20
Major company or institution
PatentBrief Impact Score — based on citation count, claim breadth, recency, and assignee scale. Not a legal assessment.
Heuristic Value Estimate
What this patent might be worth
$80K – $256K
Midpoint $160K · 5.2 yr remaining · industry ×2.2
Heuristic only — blends forward/backward citation counts, claim scope, time remaining, litigation history, and CPC-derived industry baseline. Real valuations need a professional appraisal.
Claim text not yet imported for this patent
The original legal language
Original claims
25 claims as filed with the patent office.
Concepts involved
Citations
Patent lineage
Cite this patent
Li, X., Yang, N., Nogueira, K., Gottlieb, R. K., & Liang, B. (2014). How Continuous Glucose Monitors Estimate Blood Sugar Levels Accurately (U.S. Patent No. 8,882,665). U.S. Patent and Trademark Office. https://patentbrief.org/patent/us/8882665/method-andor-system-for-multicompartment-analyte-monitoring-8882665
Auto-generated from the patent record. Double-check author order and the issue date against the official USPTO document before submitting.
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Common Questions
Frequently Asked Questions
What does How Continuous Glucose Monitors Estimate Blood Sugar Levels Accurately cover?
This patent describes a method for accurately estimating blood glucose levels by accounting for the natural delay in glucose moving between interstitial fluid and blood, using sensor data and its rate of change.
Who owns patent US 8882665?
Medtronic Minimed owns this patent, granted in 2014.
When does this patent expire?
This patent is expected to expire on October 26, 2031, when the invention enters the public domain.
What is patent US 8882665 cited by?
This patent has been cited by 9 later patents that build on its ideas.
What problem does this patent solve?
This technology is fundamental to continuous glucose monitoring (CGM) devices, which are critical for managing diabetes. By accurately estimating blood glucose from interstitial fluid, it allows people with diabetes to track their glucose trends in real-time without frequent finger-prick tests. This improves daily management, helps prevent dangerous high or low blood sugar events, and informs insulin dosing decisions.
What does this patent NOT cover?
Does not cover systems that measure analyte levels directly in the first physiological compartment (e.g., a finger-prick blood glucose meter).
Same assignee
More from Medtronic Minimed
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