ADVIA CENTAUR CA19-9

Additional Manufacturer Narrative

SIEMENS INVESTIGATED AN OUTSIDE OF THE UNITED STATES (OUS) CUSTOMER REPORT OF DISCORDANT ELEVATED (> REFERENCE RANGE) ADVIA CENTAUR XP CA19-9 RESULTS ON 2 PATIENT SAMPLES COMPARED TO LOWER RESULTS (<REFERENCE RANGE) WHEN THE SAMPLES WERE TESTED WITH ALTERNATE TEST METHODS. THE INITIAL DISCORDANT RESULTS WERE NOT REPORTED TO THE PHYSICIAN(S). THE LOWER RESULTS WERE IN AGREEMENT WITH PATIENT CLINICAL PICTURES AND WERE BELIEVED TO BE CORRECT. THERE ARE NO ALLEGATIONS OF PATIENT HARM, CHANGES IN TREATMENT, OR DELAYS OF DIAGNOSIS IN ASSOCIATION WITH THIS EVENT. BOTH PATIENTS HAVE A HISTORY OF OVARIAN TUMORS. NO INFORMATION ON MEDICATIONS/SUPPLEMENTS TAKEN BY THESE PATIENTS COULD BE PROVIDED. AS PART OF TROUBLESHOOTING, THE CUSTOMER TREATED THE SAMPLES WITH PEG600 (POLYETHELYNE GLYCOL) AND TESTED ON THE ADVIA CENTAUR XP. RESULTS WERE LOWER AND SIMILAR TO THE ALTERNATE METHOD RESULTS WHICH IS CONSISTENT WITH PRECIPITATION OF ANTIBODIES IN THE SAMPLES INTERFERING WITH THE ADVIA CENTAUR CA 19-9 ASSAY. THE SAMPLES WERE NOT TREATED WITH HETEROPHILIC BLOCKING TUBE (HBT). THERE IS NO REMAINING SAMPLE VOLUME FOR FURTHER INVESTIGATION. THE EXPECTED VALUES SECTION OF THE ADVIA CENTAUR XP CA 19-9 INSTRUCTIONS FOR USE (IFU) INDICATES 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 LIMITATIONS SECTION OF THE ADVIA CENTAUR XP CA 19-9 IFU STATES: "DO NOT INTERPRET SERUM LEVELS OF CA 19-9 AS ABSOLUTE EVIDENCE OF THE PRESENCE OR THE ABSENCE OF MALIGNANT DISEASE. BEFORE TREATMENT, PATIENTS WITH CONFIRMED GI CARCINOMA FREQUENTLY HAVE LEVELS OF CA 19-9 WITHIN THE RANGE OBSERVED IN HEALTHY INDIVIDUALS. ADDITIONALLY, ELEVATED LEVELS OF CA 19-9 CAN BE OBSERVED IN PATIENTS WITH NONMALIGNANT DISEASES. MEASUREMENTS OF CA 19-9 SHOULD ALWAYS BE USED IN CONJUNCTION WITH OTHER DIAGNOSTIC PROCEDURES, INCLUDING INFORMATION FROM THE PATIENT¿S CLINICAL EVALUATION." "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. PATIENTS ROUTINELY EXPOSED TO ANIMALS OR TO ANIMAL SERUM PRODUCTS CAN BE PRONE TO THIS INTERFERENCE AND ANOMALOUS VALUES MAY BE OBSERVED. ADDITIONAL INFORMATION MAY BE REQUIRED FOR DIAGNOSIS." BASED ON THE AVAILABLE INFORMATION, THE CAUSE OF THE DISCORDANT RESULTS IS CONSISTENT WITH SAMPLE SPECIFIC INTERFERENCE. A PRODUCT ISSUE WAS NOT IDENTIFIED. THE CUSTOMER IS OPERATIONAL, AND THE REPORTED ISSUE WAS RESOLVED BY ROUTINE TROUBLESHOOTING.

Description of Event or Problem

CUSTOMER REPORTED AN OBSERVATION OF DISCORDANT ELEVATED ADVIA CENTAUR XP CA19-9 RESULTS ON 2 PATIENT SAMPLES COMPARED TO LOWER RESULTS WHEN THE SAMPLES WERE TESTED WITH ALTERNATE TEST METHODS. THE INITIAL DISCORDANT RESULTS WERE NOT REPORTED TO THE PHYSICIAN(S). THE LOWER RESULTS WERE IN AGREEMENT WITH PATIENT CLINICAL PICTURES AND WERE BELIEVED TO BE CORRECT. THERE ARE NO ALLEGATIONS OF PATIENT HARM, CHANGES IN TREATMENT, OR DELAYS OF DIAGNOSIS IN ASSOCIATION WITH THIS EVENT.