ELECSYS CA 19-9

Additional Manufacturer Narrative

THE COBAS 6000 E601 MODULE SERIAL NUMBER IS (B)(6). THE SAMPLE WAS REQUESTED AND RECEIVED FOR INVESTIGATION. THE INVESTIGATION IS ONGOING.

Description of Event or Problem

THERE WAS AN ALLEGATION OF QUESTIONABLE HIGH ELECSYS CA 19-9 RESULTS FROM THE COBAS 6000 E601 MODULE FOR ONE PATIENT. THE INITIAL RESULT FROM THE E601 MODULE WAS 101.4 U/ML. THE REPEAT RESULT WAS 97.34 U/ML. THE RESULTS ON A SNIBE ANALYZER WERE 4.06 U/ML AND 4.49 U/ML. THE RESULT ON A BECKMAN ANALYZER WAS 4.97 U/ML. THE QUESTIONABLE RESULTS WERE NOT RELEASED OUTSIDE OF THE LABORATORY. THE ROCHE RESULTS WERE QUESTIONED AS THEY DID NOT MATCH THE PATIENT'S CLINICAL DIAGNOSIS.

Additional Manufacturer Narrative

THE PATIENT SAMPLE WAS RECEIVED FOR INVESTIGATION. QC WAS PASSING PRIOR TO THE EVENT, THEREFORE A GENERAL REAGENT PRODUCT PROBLEM COULD BE EXCLUDED. IN THE ROCHE INVESTIGATION LABORATORY, DESPITE LOWER THAN THE CUSTOMER RESULTS (THE INVESTIGATION LABORATORY RESULT = 63.3 U/ML VS. CUSTOMER RESULT OF 97.34 U/ML, WITH A DEVIATION OF -35%), THE CA 19-9 RESULT OF THE SAMPLE ON E601 STILL EXCEEDED THE REFERENCE RANGE, WHICH WAS CONSISTENT WITH THE CUSTOMER TO A CERTAIN EXTENT. THE DECREASED VALUE MAY BE DUE TO THE INSTABILITY DURING THE LONG-TERM STORAGE, TRANSPORT OR THAWING OF THE SAMPLE. AN OBVIOUS DEVIATION WAS FOUND AFTER THE POLYETHYLENE GLYCOL (PEG) TREATMENT OF THE SAMPLE, INDICATING THE EXISTENCE OF A MACRO-MOLECULAR INTERFERENCE. AN OBVIOUS DEVIATION WAS FOUND AFTER THE HETEROPHILIC BLOCKING TUBE (HBT) TREATMENT OF THE SAMPLE, INDICATING THE EXISTENCE OF A HETEROPHILIC ANTIBODY INTERFERENCE. THE INVESTIGATION DETERMINED THAT A MACRO-MOLECULAR AND HETEROPHILIC ANTIBODY INTERFERENCE CAUSED THE FALSELY ELEVATED CA 19-9 RESULTS. PER PRODUCT LABELING, "IN RARE CASES, INTERFERENCE DUE TO EXTREMELY HIGH TITERS OF ANTIBODIES TO ANALYTE-SPECIFIC ANTIBODIES, STREPTAVIDIN OR RUTHENIUM CAN OCCUR. THESE EFFECTS ARE MINIMIZED BY SUITABLE TEST DESIGN."