SODIUM ELECTRODE

Additional Manufacturer Narrative

THE COBAS C 303 ANALYTICAL UNIT SERIAL NUMBER IS (B)(6). THE COBAS PRO ANALYTICAL UNIT SERIAL NUMBER IS (B)(6). A FIELD SERVICE ENGINEER (FSE) PERFORMED A DECONTAMINATION OF THE ION-SELECTIVE ELECTRODE (ISE) FLOWPATH. NO CAUSE WAS ESTABLISHED. AN ISE CHECK WAS PERFORMED FOR VERIFICATION. THE INVESTIGATION IS ONGOING.

Description of Event or Problem

THERE WAS AN ALLEGATION OF QUESTIONABLE SODIUM ELECTRODE RESULTS FROM THE COBAS C 303 ANALYTICAL UNIT FOR 2 PATIENTS. PATIENT 1'S INITIAL RESULT WITH A COBAS PRO WAS 148 MMOL/L. THE REPEAT RESULT ON THE COBAS PURE C303 ANALYZER WAS 139 MMOL/L. PATIENT 2'S INITIAL RESULT ON THE COBAS PURE C303 WAS 150 MMOL/L. THE FIRST REPEAT RESULT WAS 148 MMOL/L. THE SECOND REPEAT RESULT WAS 144 MMOL/L.

Additional Manufacturer Narrative

QC AND CALIBRATION WERE PASSING AT THE TIME OF THE EVENT. THE PROVIDED ALARM TRACE DID NOT CONTAIN A CONSPICUOUS EVENT. DURING A SECOND VISIT, THE FIELD SERVICE ENGINEER (FSE) REPLACED THE REFERENCE ELECTRODE, SAMPLE PROBE, AND DILUTION VESSEL BEFORE SUCCESSFULLY VERIFYING SYSTEM PRECISION. THE INVESTIGATION WAS UNABLE TO DETERMINE A DIRECT ROOT CAUSE; HOWEVER, THE SERVICE ACTIONS HAVE RESOLVED THE ISSUE.