ATELLICA IM CA 19-9

Additional Manufacturer Narrative

A CUSTOMER FROM UNITED STATES REPORTED OBSERVATION OF DISCORDANCE BETWEEN NEAT AND DILUTED RESULTS WITH ATELLICA IM CA 19 9 (CA 19 9). THE CALIBRATION WAS VALID, AND QUALITY CONTROL (QC) RECOVERED WITHIN THE LABORATORY ESTABLISHED RANGES. THE ASSAY'S INSTRUCTIONS FOR USE (IFU) STATES THE FOLLOWING, UNDER INTERPRETATION OF RESULTS: "RESULTS OF THIS ASSAY SHOULD ALWAYS BE INTERPRETED IN CONJUNCTION WITH THE PATIENT'S MEDICAL HISTORY, CLINICAL PRESENTATION, AND OTHER FINDINGS." SIEMENS IS EVALUATING THE EVENT.

Description of Event or Problem

THE CUSTOMER REPORTS OBSERVATION OF DISCORDANCE BETWEEN NEAT AND DILUTED RESULTS WITH ATELLICA IM CA 19 9 (CA 19 9), LOT 546. THE AFFECTED PATIENT¿S SAMPLES WERE DRAWN INTO TWO COLLECTION TUBES. FOR THE FIRST SAMPLE, AN INITIAL RESULT WITH AN ABOVE ASSAY RANGE FLAG WAS OBTAINED. THE SAMPLE WAS THEN DILUTED (1:10) AND RETESTED ON THE ORIGINAL ANALYZER, WHICH OBTAINED A HIGHER RESULT. ON THE FOLLOWING DAY, THE SAME SAMPLE WAS RETESTED NEAT WHICH OBTAINED A LOWER RESULT. FOR THE SECOND SAMPLE, THE INITIAL NEAT TEST OBTAINED A LOWER RESULT. ON THE FOLLOWING DAY, THE SAME SAMPLE WAS RETESTED ON THE ORIGINAL ANALYZER, WHICH OBTAINED A RESULT WITH ABOVE ASSAY RANGE FLAG. THE SAMPLE WAS THEN DILUTED (1:10) AND OBTAINED A HIGHER RESULT. THE EXPECTED RESULT FOR THE AFFECTED PATIENT REMAINS UNKNOWN. HOWEVER, THE CUSTOMER ALLEGED DISCORDANCE BETWEEN THE NEAT AND DILUTED RESULTS. THERE ARE NO ALLEGATIONS OF PATIENT HARM, CHANGES IN TREATMENT, OR DELAYS OF DIAGNOSIS OR TREATMENT RESULTING FROM THE OBSERVED RESULT DISCORDANCE.

Additional Manufacturer Narrative

MDR 1219913-2025-00110 WAS INITIALLY FILED ON 06-JUN-2025. ADDITIONAL INFORMATION (29-JUL-2025): SIEMENS CONCLUDED INVESTIGATION FOR A CUSTOMER COMPLAINT OF OBSERVATION OF DISCORDANCE WITH ATELLICA IM CA 19 9 (CA 19 9) BETWEEN NEAT AND DILUTED RESULTS. SIEMENS EVALUATED THE INSTRUMENT DATA, AND THE INFORMATION PROVIDED BY THE CUSTOMER. SIEMENS REVIEWED THE ATELLICA IM CA19-9 DILUTION RECOVERY WHICH INCLUDED BOTH MANUAL AND AUTO 1:10 DILUTIONS WITH MULTIPLE REAGENT LOTS INCLUDING 052541, 052543 AND 052545 AND CONFIRMED THAT ATELLICA IM CA 19-9 DILUTION RECOVERY WAS CONSISTENT WITH DESIGN VERIFICATION PERFORMANCE. IT WAS NOTED THAT DILUTION-RECOVERY PERFORMANCE WAS NOT CONSISTENT ACROSS ALL SAMPLES. THERE IS A POSSIBILITY THAT CERTAIN PATIENT SAMPLES COULD DEMONSTRATE DILUTION OVER-RECOVERY IN MUCIN/MUCIN-LIKE ASSAYS, SUCH AS CA 19-9. CA 19-9 IS A MUCIN PROTEIN, AND NONLINEAR DILUTION WITH INCREASED ANTIGEN RECOVERY IS COMMONLY OBSERVED IN IMMUNOASSAYS DETECTING MUCINS. MUCIN GLYCOPROTEINS TEND TO AGGREGATE, BURYING THE SUGAR RESIDUES. WHEN DILUTED, THESE CLUSTERS CAN BREAK APART, MAKING THE SUGAR RESIDUES THE CA 19-9 ANTIBODY BINDS TO MORE ACCESSIBLE WHICH CAN RESULT IN AN INCREASE, OR "OVER-RECOVERY" IN DILUTED DOSE. HENCE, THERE IS A NOTE IN THE DILUTION RECOVERY SECTION OF THE ATELLICA IM CA 19-9 INSTRUCTIONS FOR USE (IFU) INDICATING "SAMPLE-DEPENDENT NONLINEAR DILUTIONS CAN BE OBSERVED." [REFERENCE: WILD D, ED. THE IMMUNOASSAY HANDBOOK. 4TH ED. OXFORD, UK: ELSEVIER SCIENCE; 2013:842] THE CUSTOMER CONFIRMED THAT THE PATIENT WAS A NEWLY DIAGNOSED PATIENT, AND THE REPEATED VALUES CORRELATED TO PATIENTS' DIAGNOSIS. BASED ON THE AVAILABLE INFORMATION, THE CAUSE OF THE DISCORDANT RESULT WAS UNABLE TO BE DETERMINED AND THE ISSUE WAS ISOLATED TO THE AFFECTED PATIENT SAMPLE. THE ISSUE WAS RESOLVED BY ROUTINE TROUBLESHOOTING. A PRODUCT PROBLEM HAS NOT BEEN IDENTIFIED. CUSTOMER IS OPERATIONAL; NO FURTHER ACTIONS ARE REQUIRED. IN SECTION H6 OF THIS REPORT, THE INVESTIGATION FINDING AND CONCLUSION CODES WERE UPDATED BASED ON THE INVESTIGATION RESULTS.