SODIUM ELECTRODE

Additional Manufacturer Narrative

THE COBAS PRO ANALYZER SERIAL NUMBER WAS (B)(6).

Description of Event or Problem

THE INITIAL REPORTER QUESTIONED LOW RESULTS FOR MULTIPLE PATIENT SAMPLES TESTED FOR SODIUM ELECTRODE (NA) ON A COBAS PRO ISE ANALYTICAL UNIT. DISCREPANT RESULTS WERE PROVIDED FOR 2 PATIENT SAMPLES. PATIENT 1 INITIAL RESULT WAS 128.8 MMOL/L. THE REPEAT RESULT WAS 136 MMOL/L. PATIENT 2 INITIAL RESULT WAS 124.2 MMOL/L. THE REPEAT RESULT WAS 132.6 MMOL/L. THE SAMPLES WERE REPEATED ON A C303 ANALYZER. THE REPEAT RESULTS WERE BELIEVED TO BE CORRECT.

Additional Manufacturer Narrative

CALIBRATION AND QC WERE ACCEPTABLE BEFORE THE EVENT. NO PREANALYTICAL ISSUES WERE IDENTIFIED. THE ALARM TRACE DATA SHOWED MULTIPLE CALIBRATION ERRORS AND SAMPLE PROBE ABNORMAL ASPIRATION ERRORS. THE FIELD SERVICE ENGINEER (FSE) AND FIELD APPLICATION SPECIALIST (FAS) VISITED THE CUSTOMER SITE. THE CUSTOMER HAD PERFORMED RACK MAINTENANCE BETWEEN CALIBRATIONS FOR TROUBLESHOOTING PURPOSES. THE CUSTOMER'S STANDARD DEVIATION (SD) QC RANGES WERE WIDER COMPARED TO THEIR OTHER INSTRUMENT ONSITE; AFTER THE EVENT, THESE RANGES WERE NARROWED. IT WAS NOTED THAT FLOWPATH CLEANING HAD NOT BEEN PERFORMED SINCE DEC-2025 (ONE MONTH OVERDUE). INSTRUMENT ADJUSTMENTS WERE CHECKED, AND PRECISION TESTING WAS COMPLETED. THE INVESTIGATION DETERMINED THE EVENT WAS DUE TO A CUSTOMER MAINTENANCE ISSUE. A PRODUCT ISSUE WAS NOT FOUND.