COBAS U 601 URINE ANALYZER

Additional Manufacturer Narrative

THE INVESTIGATION IDENTIFIED A SOFTWARE DEFECT IN THE CASSETTE-EMPTY HANDLING LOGIC INTRODUCED IN SOFTWARE VERSION 2.4.0. DUE TO ASYNCHRONOUS SYSTEM TIMING, THE CASSETTE-EMPTY CONDITION MAY BE DETECTED WHILE THE LAST STRIP OF A RUN IS ALREADY IN THE PIPETTING/MEASUREMENT PROCESS. IN THIS SCENARIO, THE SOFTWARE MAY PREMATURELY INTERRUPT THE FINAL MEASUREMENT BEFORE IT IS FULLY FINALIZED AND BEFORE THE INTERNAL MEMORY QUEUE IS CLEARED. AS A RESULT, THE INCOMPLETE MEASUREMENT REMAINS IN THE SYSTEM MEMORY QUEUE, WHICH CAN LEAD TO A MISALIGNMENT BETWEEN PROCESSED SAMPLES AND REPORTED STRIP RESULTS. THE BEHAVIOR CAN ONLY OCCUR UNDER A RARE COMBINATION OF SPECIFIC TIMING AND WORKFLOW CONDITIONS WHEN THE STRIP CASSETTE BECOMES EMPTY DURING PROCESSING OF THE FINAL SAMPLE OF A RUN. THE ISSUE CAN ONLY OCCUR IF ALL OF THE FOLLOWING CONDITIONS ARE MET SIMULTANEOUSLY: THE NUMBER OF REMAINING STRIPS EXACTLY MATCHES THE NUMBER OF SAMPLES LEFT IN THE CURRENT RUN. THE FINAL AVAILABLE STRIP IS ALREADY IN ACTIVE PIPETTING/MEASUREMENT FOR THE LAST SAMPLE. THE CASSETTE-EMPTY CONDITION IS DETECTED DURING THIS MEASUREMENT DUE TO SYSTEM TIMING. THE OPERATOR RESUMES OPERATION AFTER CASSETTE REPLACEMENT WITHOUT PERFORMING A SYSTEM INITIALIZATION.

Description of Event or Problem

WE RECEIVED AN ALLEGATION OF A SAMPLE MISMATCH FOR EIGHTY (80) URINE PATIENT SAMPLES TESTED ON THE COBAS U 601 URINE ANALYZER. THE REPORTER STATED THAT SOME PATIENT SAMPLES HAD AN ERYTHROCYTE RESULT OF "+3" OR "+4", BUT NO ERYTHROCYTES WERE DETECTED IN THE MICROSCOPIC READING. THEY SUSPECT A SAMPLE MISMATCH, AS THE SAMPLE IN ONE RACK POSITION WAS WAITING FOR THE SAMPLE RACK IN ANOTHER POSITION OF THE FOLLOWING RACK TO BE COMPLETED BEFORE THE RESULT WAS REPORTED.

Additional Manufacturer Narrative

THE SW COBAS 6500 SOFTWARE VERSION IS V2.4.0. THE CUSTOMER STATED THAT THERE MAY HAVE BEEN AN ALARM OF LOW WATER SUPPLY, AND THEY OPENED THE COVER DURING THE OPERATION. THE INVESTIGATION IS ONGOING.