MAUDE Adverse Event Report: ROCHE DIAGNOSTICS COBAS 4000 C311 STAND ALONE SYSTEM; CLINICAL CHEMISTRY ANALYZER

Catalog Number	04826876001
Medical Device Problem Code	High Test Results (2457)
Health Effect - Clinical Code	No Clinical Signs, Symptoms or Conditions (4582)
Date of Event	02/20/2026
Type of Reportable Event	Malfunction
Event or Problem Description
We received an allegation of a questionable high potassium electrode result for 1 patient sample tested on a cobas 4000 c311 stand alone system.Initial result: 4.06 mmol/l.Replacing the electrodes by the customer prompted the repeat of the sample.Repeat result: 4.56 mmol/l.The initial result was deemed to be correct as it matched the patient's previous results.No questionable result was reported outside the laboratory.
Additional Manufacturer Narrative
The potassium electrode lot number was eyp39.The expiration date was not provided.The qc was acceptable.The customer performed some troubleshooting activities, including replacing all electrodes, cleaning, and conditioning the on-selective electrode (ise) flowpath.Ise checks, calibration, and qc were performed, and they were within specifications.The investigation is ongoing.
Additional Manufacturer Narrative
The calibration was last performed on 20-feb-2026, and it was acceptable.The alarm trace did not show any abnormalities.The field service engineer checked the system and found no cause for the event.He performed maintenance, replaced all electrodes, and cleaned and conditioned the ion-selective electrode (ise) flow path.Ise check, calibration, and qc were executed successfully.No further issues were reported after the service visit.The investigation did not identify a product problem.The cause of the event could not be determined.

• Brand Name: COBAS 4000 C311 STAND ALONE SYSTEM
• Common Device Name: CLINICAL CHEMISTRY ANALYZER
• Manufacturer (Section D): ROCHE DIAGNOSTICS; 9115 hague road; indianapolis IN 46250 0457
• Manufacturer (Section G): HITACHI HIGH TECH CORP.; 882 ichige hitachinaka; ibaraki 312-8 504; JA 312-8504
• Manufacturer Contact: natalie catton ; 9115 hague road; indianapolis, IN 46250
• MDR Report Key: 24611541
• Report Number: 1823260-2026-00932
• Device Sequence Number: 10334721
• Product Code: JJE
• UDI-Device Identifier: 04015630925551
• UDI-Public: 04015630925551
• Combination Product (Y/N): N
• Initial Reporter State: CA
• Initial Reporter Country: US
• PMA/510(K) Number: K060373
• Number of Events Summarized: 1
• Summary Report (Y/N): N
• Serviced by Third Party (Y/N): Unknown
• Reporter Type: Manufacturer
• Report Source: Health Professional,User Facility
• Initial Reporter Occupation: Other Health Care Professional
• Type of Report: Initial,Followup
• Report Date (Section B): 04/13/2026

1 Device was Involved in the Event

1 Patient was Involved in the Event

• Is this an Adverse Event Report?: No
• Is this a Product Problem Report?: Yes
• Operator of Device: Health Professional
• Device Catalogue Number: 04826876001
• Was Device Available for Evaluation?: Yes
• Is the Reporter a Health Professional?: Yes
• Type of Report(Section G): Follow-Up
• Initial Date Received by Manufacturer: 02/23/2026
• Supplement Date Received by Manufacturer: 03/24/2026
• Initial Report FDA Received Date: 03/16/2026
• Supplement Report FDA Received Date: 04/13/2026
• Was Device Evaluated by Manufacturer? (Y/N): Yes
• Is the Device Labeled for Single Use? (Y/N): No
• Is This a Single-Use Device that was Reprocessed and Reused on a Patient? (Y/N): No
• Patient Sequence Number: 1
• Patient Sex: Unknown