ATELLICA IM CA 19-9 (CA 19-9)

Description of Event or Problem

THE CUSTOMER REPORTS OBSERVATION OF ELEVATED ATELLICA IM CA 19-9 (CA 19-9) RESULTS WHICH WERE DISCORDANT RELATIVE TO ALTERNATE-METHOD TESTING WHEN USING CA 19-9 LOT 548. AN INITIAL MILDLY ELEVATED ATELLICA IM CA 19-9 RESULT WAS OBTAINED FOR AN 81-YEAR-OLD WOMAN DIAGNOSED WITH NEOPLASIA. THIS RESULT WAS QUESTIONED AS IT WAS HIGHER THAN EXPECTED FOR THIS PATIENT. THE SAMPLE WAS RE-TESTED USING AN ALTERNATE METHOD (VIDAS), AND A LOWER RESULT (30.93 U/ML) WAS PRODUCED. THIS RESULT WAS CONSIDERED CONSISTENT WITH THE PATIENT¿S CLINICAL HISTORY, AND ACCEPTED AS CORRECT. SUSPECTING POSSIBLE SAMPLE INTERFERENCE, THE CUSTOMER DILUTED THE SAMPLE 10-FOLD FOR ANOTHER ATELLICA IM CA 19-9 TEST, AND A SUBSTANTIALLY HIGHER RESULT WAS OBTAINED. ADDITIONAL DILUTION PRODUCED AN EVEN HIGHER RESULT FOR THIS SAMPLE. THERE ARE NO ALLEGATIONS OF PATIENT HARM OR ANY ADVERSE CONSEQUENCES IN ASSOCIATION WITH THE OBSERVED DISCORDANCE.

Additional Manufacturer Narrative

A CUSTOMER FROM OUTSIDE THE UNITED STATES REPORTS OBSERVATION OF ELEVATED ATELLICA IM CA 19-9 (CA 19-9) RESULTS WHICH WERE DISCORDANT RELATIVE TO ALTERNATE-METHOD TESTING. SIEMENS IS INVESTIGATING.

Additional Manufacturer Narrative

A CUSTOMER FROM OUTSIDE THE UNITED STATES REPORTED OBSERVATION OF ELEVATED ATELLICA CI CA 19-9 (CA 19-9) RESULTS WHICH WERE DISCORDANT RELATIVE TO ALTERNATE-METHOD TESTING. UPDATE, 26-MAR-2026: SIEMENS HAS CONCLUDED THE INVESTIGATION. QUALITY CONTROL (QC) RESULTS WERE WITHIN EXPECTED RANGES AT THE TIME OF TESTING, AND NO ISSUES WERE REPORTED FOR ANY OTHER PATIENT SAMPLES PROCESSED AROUND THIS TIME. NO INFORMATION WAS AVAILABLE REGARDING MEDICATIONS OR SUPPLEMENTS THE AFFECTED PATIENT MAY HAVE BEEN TAKING. AS THE CUSTOMER SUSPECTED SAMPLE INTERFERENCE, THEY TESTED A SERIES OF DILUTIONS OF THE SAMPLE, WITH INCREASINGLY HIGHER RESULTS. IT IS NOTED THAT DILUTING LOW-CONCENTRATION SAMPLES CAN PRODUCE ARTIFICIALLY ELEVATED RESULTS, AS DILUTION AT OR NEAR THE ASSAY MEASURING LIMIT MAY CAUSE THE FINAL RESULT TO INCREASE WHEN THE DILUTION FACTOR IS APPLIED. A REPEAT TEST OF THE UNDILUTED SAMPLE PRODUCED A RESULT SOMEWHAT HIGHER THAN THE INITIAL ELEVATED RESULT (64.45 U/ML). THE CUSTOMER ALSO TESTED THE SAMPLE FOLLOWING PRE-TREATMENT WITH A NONSPECIFIC ANTIBODY BLOCKING TUBE (NABT) AND A HETEROPHILIC ANTIBODY BLOCKING TUBE (HBT), AND NEITHER TREATMENT PRODUCED ANY DECREASE IN THE ATELLICA IM CA 19-9 RESULT. THE ASSAY¿S INSTRUCTIONS FOR USE (IFU) CONTAINS THE FOLLOWING WARNING STATEMENTS: THE CONCENTRATION OF CA 19-9 IN A GIVEN SPECIMEN, AS DETERMINED BY ASSAYS FROM DIFFERENT MANUFACTURERS, CAN VARY DUE TO DIFFERENCES IN ASSAY METHODS AND REAGENT SPECIFICITY. VALUES OBTAINED WITH DIFFERENT ASSAY METHODS CANNOT BE USED INTERCHANGEABLY. BASED ON THE AVAILABLE INFORMATION, THE CAUSE OF THE FALSELY ELEVATED RESULT IS LIKELY ASSOCIATED WITH A SAMPLE-SPECIFIC INTERFERENT. THERE IS NO EVIDENCE OF A SYSTEMIC REAGENT OR INSTRUMENT ISSUE. THE CUSTOMER REMAINS OPERATIONAL, AND THE REPORTED ISSUE WAS RESOLVED BY ROUTINE TROUBLESHOOTING WHICH INCLUDED ALTERNATE-METHOD TESTING AND SAMPLE INVESTIGATION USING NABT AND HBT PRE-TREATMENT. NOTE: IN SECTION H6, THE CODES FOR INVESTIGATION FINDINGS AND INVESTIGATION CONCLUSIONS HAVE BEEN UPDATED.