SODIUM ELECTRODE

Description of Event or Problem

WE RECEIVED AN ALLEGATION OF QUESTIONABLE SODIUM ELECTRODE RESULTS FOR 1 PATIENT SAMPLE TESTED ON A COBAS C 303 ANALYTICAL UNIT. THE INITIAL RESULT WAS 160 MMO/L. THE PHYSICIAN QUESTIONED THE INITIAL RESULT AS IT WAS HIGHER THAN THE PATIENT'S HISTORY AND MEDICAL CONDITION. THE SAMPLE WAS THEN REPEATED ON A DIFFERENT ANALYTICAL UNIT PER THE CUSTOMER'S ROUTINE PROCEDURES, AND THE REPEAT RESULT WAS 145 MMOL/L. THE LOWER RESULT WAS CONSISTENT WITH THE PATIENT'S HEALTH.

Additional Manufacturer Narrative

THE COBAS C 303 ANALYTICAL UNIT SERIAL NUMBER WAS (B)(6). THE VISUAL CHECK OF THE SAMPLE SHOWED NO ABNORMALITIES. THE QC WAS ACCEPTABLE. THE FIELD SERVICE ENGINEER FOUND THAT THE SODIUM ELECTRODE WAS HAVING ISSUES. HE REPLACED THE PINCH VALVE TUBING, THE SIPPER NOZZLE, THE SIPPER TUBING, THE VACUUM NOZZLE, THE DILUTION VESSEL, AND THE SODIUM ELECTRODE. REAGENT PRIMES, ISE CHECKS, CALIBRATION, QC, AND PRECISION STUDIES WERE PERFORMED, AND THEY WERE WITHIN SPECIFICATIONS. THE INVESTIGATION IS ONGOING.

Additional Manufacturer Narrative

THE PROVIDED ALARM TRACE SHOWED ABNORMAL ASPIRATION (SAMPLE PIPETTER), SAMPLE SHORT, AND SAMPLE CLOT DETECTION ALARMS. THESE ARE INDICATORS OF POSSIBLE POOR SAMPLE QUALITY. THE SODIUM ELECTRODE WAS INSTALLED ON (B)(6) 2026 AND WAS REPORTED TO HAVE 80% LIFE LEFT. THE ELECTRODE WAS NOT DUE FOR REPLACEMENT UNTIL (B)(6) 2026. THE INVESTIGATION DID NOT IDENTIFY A PRODUCT PROBLEM. THE CAUSE OF THE EVENT COULD NOT BE DETERMINED.