ELECSYS CA 19-9

Additional Manufacturer Narrative

THE CUSTOMER'S UNIT 1 SERIAL NUMBER WAS (B)(6). THE CUSTOMER'S UNIT 2 SERIAL NUMBER WAS NOT PROVIDED. THE SERIAL NUMBER FOR THE E801 ANALYZER USED AT THE INVESTIGATION SITE WAS NOT PROVIDED. THE COMPETITOR METHOD AT THE EXTERNAL LABORATORY WAS FUJIREBIO LUMIPULSE. THE INVESTIGATION IS ONGOING.

Description of Event or Problem

THE INITIAL REPORTER COMPLAINED OF DISCREPANT RESULTS FOR 1 PATIENT SAMPLE TESTED FOR ELECSYS CA 19-9 (CA 19-9) ON 2 COBAS PRO SB ANALYZERS (UNIT 1 AND UNIT 2). THE INITIAL RESULT WITH NO DILUTION FROM UNIT 1 WAS > 1000 U/ML. THE REPEAT WITH A 1:5 DILUTION FROM UNIT 2 WAS 505.0 U/ML. THE REPEAT WITH A 1:2 DILUTION FROM UNIT 1 WAS 758.0 U/ML. THE SAMPLE WAS SUBMITTED FOR INVESTIGATION AND TESTED ON A COBAS E801 ANALYZER. ON 18-APR-2025, THE RESULT WITH NO DILUTION WAS > 1000 U/ML. THE RESULT WITH A 1:2 DILUTION WAS 780 U/ML. THE RESULT WITH A 1:5 DILUTION WAS 505 U/ML. THE RESULT WITH A 1:10 DILUTION WAS 462 U/ML. THE SAMPLE WAS SENT TO AN EXTERNAL LABORATORY AND TESTED BY A COMPETITOR METHOD. ON (B)(6) 2025, THE CA 19-9 RESULT FROM THE COMPETITOR METHOD WAS 8240 U/ML.

Additional Manufacturer Narrative

SECTIONS B6 AND B7 WERE UPDATED. SECTION D4, LOT NUMBER, AND EXPIRATION DATE WERE UPDATED. SECTION D10 WAS UPDATED. SAMPLE MATERIAL WAS REQUESTED FOR INVESTIGATION.

Additional Manufacturer Narrative

SAMPLE MATERIAL WAS RECEIVED FOR INVESTIGATION, AND INTERFERENCE TESTING WAS PERFORMED. THE FOLLOWING TESTS WERE CONDUCTED: SERIAL DILUTION, TESTING WITH MODIFIED ASSAY REAGENTS, AND TREATMENT WITH A HETEROPHILIC BLOCKING TUBE (HBT). BASED ON THE RESULTS RECEIVED DURING THE INVESTIGATION, AN INTERFERENT AGAINST THE ASSAY COMPONENTS WAS CONFIRMED. PRODUCT LABELING STATES: "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." THE CUSTOMER TESTED THE PATIENT SAMPLE BY A COMPETITOR METHOD. PRODUCT LABELING STATES: "THE MEASURED CA 19-9 VALUE OF A PATIENT'S SAMPLE CAN VARY DEPENDING ON THE TESTING PROCEDURE USED....CA 19-9 VALUES DETERMINED ON PATIENT SAMPLES BY DIFFERENT TESTING PROCEDURES CANNOT BE DIRECTLY COMPARED WITH ONE ANOTHER AND COULD BE THE CAUSE OF ERRONEOUS MEDICAL INTERPRETATIONS." THE CUSTOMER USED VARIOUS DILUTION RATIOS. PRODUCT LABELING STATES: "SAMPLES WITH CA 19-9 CONCENTRATIONS ABOVE THE MEASURING RANGE CAN BE DILUTED WITH DILUENT UNIVERSAL. THE RECOMMENDED DILUTION IS 1:10 (EITHER AUTOMATICALLY BY THE ANALYZERS OR MANUALLY). THE CONCENTRATION OF THE DILUTED SAMPLE MUST BE > 50 U/ML." THE INVESTIGATION DID NOT IDENTIFY A PRODUCT PROBLEM.