MAUDE Adverse Event Report: DEXCOM, INC. DEXCOM G6 CONTINUOUS GLUCOSE MONITORING SYSTEM

Catalog Number	STS-OM-001
Medical Device Problem Code	High Readings (2459)
Health Effect - Clinical Codes	Hyperglycemia (1905); Muscle Weakness/Atrophy (1967)
Date of Event	10/28/2025
Type of Reportable Event	Serious Injury
Additional Manufacturer Narrative
(b)(4) diabetes mellitus is a known cause of hyperglycemia.
Event or Problem Description
It was reported that an inaccuracy between the continuous glucose monitor (cgm) and the blood glucose (bg) meter occurred.The sensor was inserted into the abdomen on (b)(6) 2025.On the same day, it was reported that the patient inserted a new sensor.Later that day, the patient¿s cgm was reading 400 mg/dl.The patient self-treated with an insulin injection.Despite this, the patient¿s cgm value remained at 400 mg/dl.The patient then decided to test his bg meter reading which was between 155-160 mg/dl.After a few minutes, the patient tested his bg meter reading again and it was 190 mg/dl while the cgm was reading 400 mg/dl.The patient attempted to calibrate his dexcom device but the calibration did not bring the reading into an expected range.The patient¿s cgm then rapidly started changing from 400 mg/dl to 90 mg/dl within 5 minutes and vice versa.The patient then decided to go to the emergency room (er).At the er, the patient started to feel weak and uneasy.The patient¿s bg meter reading was 350 mg/dl while the cgm was reading 116 mg/dl.The patient¿s blood pressure was also low.The patient had an mri and ct scan done.He was admitted to the icu for 2.5 days and then transferred to a regular hospital room.The patient was treated with iv fluids and iv insulin.The patient¿s cgm and tandem insulin pump were also removed.The patient was discharged on (b)(6) 2025 and still felt a little weak.On (b)(6) 2025, the patient stated he felt better and was ¿fine¿, however, he was undergoing physical therapy.Data was evaluated and the allegation was undetermined.The probable cause could not be determined via data.The reported glucose values fall within the c zone of the parkes error grid.After a few minutes, the reported glucose values fall within the b zone of the parkes error grid.The data investigation did not find blood glucose calibration values to compare to cgm values during the reported sensor session or the calibrations during the reported sensor session were in accurate range per device specifications.No additional patient or event information is available.
Additional Manufacturer Narrative
(b)(4).
Event or Problem Description
Product was provided for evaluation.The product was not evaluated because sensor has been compromised and the environment in which the system failed cannot be replicated.A probable cause could not be determined.

• Brand Name: DEXCOM G6 CONTINUOUS GLUCOSE MONITORING SYSTEM
• Common Device Name: CONTINUOUS GLUCOSE MONITOR
• Manufacturer (Section D): DEXCOM, INC.; 6340 sequence dr.; san diego CA 92121
• Manufacturer Contact: ashley spoto ; 6340 sequence dr.; san diego, CA 92121 ; 8582000200
• MDR Report Key: 23534610
• Report Number: 3004753838-2025-317529
• Device Sequence Number: 18688818
• Product Code: QBJ
• UDI-Device Identifier: 80386270000251
• UDI-Public: (01)80386270000251
• Combination Product (Y/N): N
• Initial Reporter State: FL
• Initial Reporter Country: US
• PMA/510(K) Number: DEN170088
• Number of Events Summarized: 1
• Summary Report (Y/N): N
• Serviced by Third Party (Y/N): Unknown
• Reporter Type: Manufacturer
• Report Source: Consumer
• Initial Reporter Occupation: Other
• Type of Report: Initial,Followup
• Report Date (Section B): 12/26/2025

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?: No
• Operator of Device: Lay User/Patient
• Device Catalogue Number: STS-OM-001
• Was Device Available for Evaluation?: Device Returned to Manufacturer
• Is the Reporter a Health Professional?: No
• Type of Report(Section G): Follow-Up
• Initial Date Received by Manufacturer: 10/31/2025
• Supplement Date Received by Manufacturer: 12/13/2025
• Initial Report FDA Received Date: 11/12/2025
• Supplement Report FDA Received Date: 12/26/2025
• Was Device Evaluated by Manufacturer? (Y/N): Yes
• Is the Device Labeled for Single Use? (Y/N): Yes
• Is This a Single-Use Device that was Reprocessed and Reused on a Patient? (Y/N): No
• Usage of Device: Initial
• Patient Sequence Number: 1
• Concomitant Medical Products and Therapy/Usage Dates: TANDEM TSLIM PUMP
• Outcome Attributed to Adverse Event: Hospitalization; Other
• Patient Age: 89 YR
• Patient Sex: Male
• Patient Weight: 67 KG