SODIUM ELECTRODE

Description of Event or Problem

THE INITIAL REPORTER QUESTIONED LOW RESULTS FOR 20 PATIENT SAMPLES TESTED FOR SODIUM ELECTRODE (NA) ON A COBAS 6000 C (501) MODULE. AN EXAMPLE OF DISCREPANT RESULTS WAS PROVIDED FOR 1 PATIENT SAMPLE. THE INITIAL RESULT WAS 128 MMOL/L. THE REPEAT FROM A DIFFERENT C501 MODULE WAS 134 MMOL/L. THE REPEAT RESULT WAS BELIEVED TO BE CORRECT.

Additional Manufacturer Narrative

THE C501 MODULE SERIAL NUMBER WAS (B)(6). AFTER WEEKLY MAINTENANCE WAS PERFORMED ON THE C501 MODULE IN QUESTION, THE SAME SAMPLES WERE REPEATED ON THE MODULE, AND THE RESULTS WERE CONSISTENT WITH THE REPEAT RESULTS FROM THE OTHER C501 MODULE. THE INVESTIGATION IS ONGOING.

Additional Manufacturer Narrative

THE DATA OBTAINED SHOWS THAT NO CALIBRATION WAS PERFORMED ON THE DAY OF THE EVENT. THE DATA OBTAINED SHOWS NO QC MEASUREMENTS ON THE DAY OF THE EVENT. ISE NOISE ERRORS WERE OBSERVED ON THE ALARM TRACE DATA. THE FIELD SERVICE ENGINEER (FSE) INSPECTED THE INSTRUMENT AND PERFORMED CHECKS; NO ISSUES WERE IDENTIFIED. PRECISION TEST RESULTS WERE ACCEPTABLE. THE CUSTOMER DID NOT PROVIDE ANY ADDITIONAL INFORMATION FOR THE INVESTIGATION. THE INVESTIGATION DID NOT IDENTIFY A PRODUCT PROBLEM. THE CAUSE OF THE EVENT COULD NOT BE DETERMINED.