MAUDE Adverse Event Report: DEXCOM, INC. G7 GLUCOSE SENSOR; INTEGRATED CONTINUOUS GLUCOSE MONITORING SYSTEM, FACTORY CALIBRATED

Lot Number	1726037003
Medical Device Problem Code	Incorrect, Inadequate or Imprecise Result or Readings (1535)
Health Effect - Clinical Codes	Hyperglycemia (1905); Hypoglycemia (1912); Blurred Vision (2137)
Date of Event	03/18/2026
Type of Reportable Event	Serious Injury
Event or Problem Description
I am a diabetic and have used a dexcom g7 glucose sensor for just under two years.I have always used the 10-day sensor and i wear them continuously.Previously, my diabetes was treated with short- and long-acting insulin and metformin.In (b)(6) 2025, i stopped insulin therapy and it was replaced with mounjaro.On (b)(6) 2026 my dexcom g7 sensor failed.This failure followed the failure of three consecutive sensors i used prior to the current one.In all four cases, the sensors began reporting wildly inaccurate readings.In some cases, the readings were significantly lower than those confirmed by a finger stick blood sample or significantly higher than those confirmed by a finger stick.For example, i received an alert this morning (the day of this report) from my mobile device that my blood glucose was 40 mg/dl.I immediately tested my blood sugar with my glucose test meter.I performed three finger sticks and the readings were 120, 115, and 125.I proceeded to calibrate the g7 using the dexcom app on my mobile device.The readings from the g7 subsequently were accurate within 10% of those obtained by finger stick.However, within 45 minutes of the calibration i received a second warning alert from my mobile app that my glucose had fallen to 57 mg/dl.Previously, i received an alert that my blood glucose had exceeded the high threshold i set on dexcom's app (180 mg/dl).At the time, i was reading in bed about to fall asleep.I silenced the alert.Approximately 20 minutes later, my vision became blurry, i began sweating profusely and became shaky.I called my wife into the room and asked her to check my glucose and to bring glucose tablets.My blood pressure had dropped and it was difficult to draw blood.However, she was able to obtain two readings from the finger stick.These readings were 61 mg/dl and 57 mg/dl compared to the latest g7 reading of 182 mg/dl.These two events are by no means an exhaustive list of wildly inaccurate glucose values that have occurred regularly over this one sensor session.Moreover, it follows the failure of three consecutive sensors for precisely the same reason; that is, inaccurate readings.Something has changed with the manufacturing of these sensors although i clearly do not know what they may be.Pt-1905.Device-1535.Reference reports-mw5185699; mw5185700; mw518701.
Event or Problem Description
Additional information received on 3/26/2026 for report mw5185698 to reference report mw5185701 and to add patient codes 2137 and 1912.

• Brand Name: G7 GLUCOSE SENSOR
• Common Device Name: INTEGRATED CONTINUOUS GLUCOSE MONITORING SYSTEM, FACTORY CALIBRATED
• Manufacturer (Section D): DEXCOM, INC.
• MDR Report Key: 24674516
• Report Number: MW5185698
• Device Sequence Number: 12041683
• Product Code: QBJ
• UDI-Device Identifier: 00386270003935
• UDI-Public: 00386270003935
• Combination Product (Y/N): N
• Initial Reporter State: CT
• Initial Reporter Country: US
• Number of Events Summarized: 1
• Summary Report (Y/N): N
• Reporter Type: Voluntary
• Initial Reporter Occupation: Patient
• Type of Report: Initial,Followup
• Report Date (Section B): 03/18/2026

1 Device was Involved in the Event

1 Patient was Involved in the Event

• Is this an Adverse Event Report?: Yes
• Is this a Product Problem Report?: Yes
• Operator of Device: Lay User/Patient
• Device Lot Number: 1726037003
• Was Device Available for Evaluation?: No
• Is the Reporter a Health Professional?: No
• Type of Report(Section G): Follow-Up
• Initial Date Received by Manufacturer: Not provided
• Supplement Date Received by Manufacturer: Not provided
• Initial Report FDA Received Date: 03/24/2026
• Supplement Report FDA Received Date: 03/27/2026
• Patient Sequence Number: 1
• Concomitant Medical Products and Therapy/Usage Dates: AMLODIPINE.; FERROUS SULFATE SUPPLEMENT.; LOSARTAN.; METFORMIN.
• Outcome Attributed to Adverse Event: Other
• Patient Age: 60 YR
• Patient Sex: Male
• Patient Weight: 88 KG
• Patient Race: White