ATELLICA IM CA 19-9

Description of Event or Problem

THE CUSTOMER REPORTED OBSERVATION OF ELEVATED ATELLICA IM CA 19-9 RESULTS WHEN USING LOT# 546 WHICH WERE DISCORDANT RELATIVE TO REPEAT TESTING ON AN ALTERNATE METHOD. AN INITIAL ELEVATED ATELLICA IM CA 19-9 RESULT WAS OBTAINED FOR THE PATIENT IN QUESTION. THE SAME SAMPLE WAS REPEATED ON THE ORIGINAL ANALYZER AND OBTAINED A SIMILARLY ELEVATED RESULT. THE INITIAL ELEVATED RESULT WAS REPORTED TO THE PHYSICIAN(S), WHO QUESTIONED THE RESULT. THE SAME SAMPLE WAS TESTED AFTER PEG6000 (POLYETHYLENE GLYCOL 6000) TREATMENT ON THE SAME ANALYZER FOR TROUBLESHOOTING PURPOSES AND OBTAINED A LOWER RESULT. THEN THE SAMPLE WAS ALSO RETESTED USING AN ALTERNATE TEST METHOD (BECKMAN COULTER UNICEL DXI 800) WHICH OBTAINED A MUCH LOWER RESULT. THE LOWER RESULT OBTAINED USING THE ALTERNATE METHOD WAS CONSIDERED CORRECT BASED ON THE CLINICAL PICTURE OF THE AFFECTED PATIENT AND A CORRECTED REPORT WAS ISSUED TO THE PHYSICIAN(S). THERE ARE NO KNOWN REPORTS OF PATIENT INTERVENTION OR ADVERSE HEALTH CONSEQUENCES DUE TO THIS EVENT.

Additional Manufacturer Narrative

AN OUTSIDE OF THE UNITED STATES (OUS) CUSTOMER CONTACTED THE SIEMENS REMOTE SERVICES CENTER (RSC) AND REPORTED OBSERVATION OF ELEVATED ATELLICA IM CA 19-9 RESULTS WHICH WERE DISCORDANT RELATIVE TO REPEAT TESTING ON AN ALTERNATE METHOD. SIEMENS REVIEWED THE INSTRUMENT DATA AND THE DATA PROVIDED BY THE CUSTOMER. REAGENT AND INSTRUMENT ISSUES WERE RULED OUT BASED ON QUALITY CONTROL (QC) RECOVERY WITHIN ACCEPTABLE RANGES AND NO ISSUES WERE REPORTED WITH OTHER PATIENT SAMPLES. SIEMENS OBSERVED THAT PRETREATMENT OF THE SAMPLE WITH PEG6000 MAY HAVE PRECIPITATED ANTIBODIES THAT WERE INTERFERING WITH THE ATELLICA IM CA 19-9 ASSAY. THE ASSAY INSTRUCTIONS FOR USE (IFU), UNDER EXPECTED VALUES SECTION INDICATES THE FOLLOWING: "3.7% OF SAMPLES FROM NORMAL PATIENTS RECOVERED >37 U/ML SO A CERTAIN NUMBER OF ELEVATED RESULTS FROM NORMAL PATIENTS CAN BE EXPECTED FOR THIS ASSAY." THE ASSAY INSTRUCTIONS FOR USE (IFU), UNDER LIMITATIONS SECTION STATES THE FOLLOWING: "THE ASSAY IS NOT SUPPOSED TO BE USED AS A SCREENING TEST OR FOR DIAGNOSIS. ELEVATED LEVELS OF CA 19-9 CAN BE OBSERVED IN PATIENTS WITH NONMALIGNANT DISEASES. THE CONCENTRATION OF CA 19-9 IN A GIVEN SPECIMEN DETERMINED WITH ASSAYS FROM DIFFERENT MANUFACTURERS CAN VARY BECAUSE OF DIFFERENCES IN ASSAY METHODS, CALIBRATION, AND REAGENT SPECIFICITY. HETEROPHILIC ANTIBODIES IN HUMAN SERUM CAN REACT WITH REAGENT IMMUNOGLOBULINS, INTERFERING WITH IN VITRO IMMUNOASSAYS." BASED ON THE AVAILABLE INFORMATION, THE CAUSE OF THE DISCORDANT ELEVATED RESULT WAS CONSISTENT WITH A SAMPLE SPECIFIC INTERFERENT. THE ISSUE WAS RESOLVED BY ROUTINE TROUBLESHOOTING; A PRODUCT PROBLEM WAS NOT IDENTIFIED. THE CUSTOMER IS OPERATIONAL, AND NO FURTHER ACTIONS ARE REQUIRED.