Tracking insertion and removal times of a continuous glucose monitoring sensor
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Publication Number
US-12257045-B2
Publication Date
2025-03-25
Expiration Date
Abstract
In response to insertion of a continuous glucose monitoring (CGM) sensor into the skin of user, a CGM system compares an identifier of the sensor to any previously-stored identifiers of previously-inserted sensors. If the identifier does not match a previously-stored identifier, indicating a newly-inserted sensor, the identifier and a time stamp are stored and CGM may begin. Upon removal of the sensor, a removal time stamp is stored. If the identifier of an inserted sensor matches a previously-stored identifier, indicating a reinserted sensor, a reinsertion time is obtained and an elapsed removal time is checked to determine whether it exceeds a maximum removal time limit. If it does, CGM is halted. If it does not, CGM may continue with the reinserted sensor. Methods of tracking insertion and removal times of a CGM sensor are also provided, as are other aspects.
Core Innovation
The invention is a continuous glucose monitoring (CGM) system that continuously monitors a user’s glucose concentration level using an analyte sensor configured to be inserted into a subcutaneous region. The system applies a bias voltage to the analyte sensor and measures a resultant current or electrical signals via an analog front end to determine the glucose concentration level. A sensor unit memory stores an identifier for the analyte sensor, and a second memory stores a plurality of sensor identifiers.
At least one processor reads the identifier stored in the sensor unit memory and determines whether the identifier matches any previously-stored identifier in the second memory. When the identifier does not match, the system stores the identifier and a skin insertion time stamp generated by a real-time clock in the second memory and begins CGM operation. When removal is detected via a switch in communication with the sensor unit, the system stores a skin removal time stamp generated by the real-time clock in the second memory.
On reinsertion, when the switch detects that the analyte sensor is reinserted and the identifier matches the previously-stored identifier in the second memory, the system obtains a skin reinsertion time stamp using the real-time clock. The system determines an elapsed removal time of the analyte sensor based on the skin removal time stamp and the skin reinsertion time stamp, and determines whether the analyte sensor has exceeded a predetermined maximum removal time limit based on the elapsed removal time. Responsive to receiving an additional signal from the analyte sensor, the system prevents continued use by preventing processing of any new signals when the limit is exceeded.
The disclosed architecture includes a sensor unit with sensor unit memory and a switch configured to detect removal, and system components including a processor, a real-time clock, and second memory that may be located in an external device and/or cloud-based storage. Insertion, removal, and reinsertion-time-limit related data are stored in tables, and the system may generate alerts or error messages in response to preventing continued use. Removal detection can be based on a physical switch and/or monitoring the electrical signal or current from the analyte sensor.
Claims Coverage
The partial content explicitly provides three independent claims: one system claim and one additional system claim format, plus one method claim. Across these independent claims, the coverage centers on sensor identity tracking with a real-time clock and insertion/removal timestamps, glucose determination from analog front end measurements, and preventing continued processing when a predetermined maximum removal time limit is exceeded.
Sensor identity tracking with real-time clock timestamps
The processor reads the identifier stored in sensor unit memory, determines whether it matches previously-stored identifiers in a second memory, stores the identifier and a skin insertion time stamp generated by the real-time clock when the identifier does not match, and obtains reinsertion time stamps when an already-stored identifier is detected.
Analog front end glucose determination
The system applies a bias voltage to the analyte sensor and measures a resultant current or receives electrical signals from the analog front end, and determines the glucose concentration level based on the resultant current or the electrical signals.
Switch-based removal detection and elapsed removal time computation
The switch detects when the analyte sensor is removed from a skin surface and stores a skin removal time stamp generated by the real-time clock in the second memory; upon reinsertion with matching identifier, a skin reinsertion time stamp is obtained and an elapsed removal time is determined based on the skin removal time stamp and the skin reinsertion time stamp.
Predetermined maximum removal time limit enforcement
Responsive to receiving an additional signal from the analyte sensor, the processor determines whether the analyte sensor has exceeded a predetermined maximum removal time limit based on the elapsed removal time, and responsive to determining exceedance, preventing continued use by preventing processing of any new signals from the analyte sensor.
Across the independent claims, the key inventive combination is tracking the analyte sensor’s identity and insertion/removal history using a real-time clock and stored identifiers and time stamps, determining glucose concentration from analog front end measurements, and enforcing a predetermined maximum removal time limit by preventing processing of new signals when the sensor has been removed for too long.
Stated Advantages
Prevents continued use of the analyte sensor by preventing processing of any new signals from the analyte sensor when the analyte sensor has exceeded a predetermined maximum removal time limit.
Documented Applications
Continuous glucose monitoring (CGM) of a user’s glucose concentration level using an analyte sensor inserted into a subcutaneous region, with operation controlled based on sensor insertion and removal time limits.
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