ELECSYS CA 19-9

Additional Manufacturer Narrative

CORRECTION: INITIAL RESULT: 1000 U/ML (ACCOMPANIED BY A DATA FLAG) INSTEAD OF INITIAL RESULT: >1000 U/ML. THE CALIBRATION WAS LAST PERFORMED ON (B)(6) 2024 AND IT WAS ACCEPTABLE. THE PROVIDED ALARM TRACE SHOWED NO ABNORMALITIES ON (B)(6) 2024. THE SAMPLE WAS REQUESTED FOR INVESTIGATION ON 16-OCT-2024 AND RECEIVED ON 28-OCT-2024. THE INVESTIGATION OF THE SAMPLE REVEALED THE FOLLOWING: 1. THE RESULTS (WITHOUT DILUTION) WERE CONSISTENT WITH THE CUSTOMER'S INITIAL RESULT (>1000 U/ML). 2. THE RESULTS AFTER AUTO-DILUTION WERE SIGNIFICANTLY LOWER THAN THE DIRECT MEASURED RESULTS. 3. THE SERIES DILUTION (1:5, 1:10, 1:20) SHOWED LOW RECOVERY AND RELATIVELY POOR CORRELATION COMPARED WITH THE CONTROL SAMPLE. 4. PEG PRECIPITATION SHOWED LOW RECOVERY. BASED ON THE DILUTION AND PEG RESULTS, AN INTERFERENCE WAS CONFIRMED. THE INVESTIGATION DID NOT IDENTIFY A PRODUCT PROBLEM. THE PRODUCT PERFORMED WITHIN THE SPECIFIED LIMIT. THE ROOT CAUSE WAS DUE TO A MACRO-PROTEIN INTERFERENCE IN THE SAMPLE. 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.

Additional Manufacturer Narrative

THE COBAS E801 MODULE SERIAL NUMBER WAS (B)(6). THE CUSTOMER USES A 3RD PARTY QC. THE PRODUCT LABELING STATES: DILUTION: 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 IS ONGOING.

Description of Event or Problem

WE RECEIVED AN ALLEGATION ABOUT DISCREPANT RESULTS FOR 1 PATIENT SERUM SAMPLE TESTED WITH ELECSYS CA 19-9 ASSAY ON A COBAS E801 MODULE. INITIAL RESULT: >1000 U/ML. REPEAT RESULT: 133 U/ML (TESTED WITH AN AUTOMATIC 10 TIMES DILUTION). THE SAMPLE OBTAINED AN ADDITIONAL REPEAT VALUE OF >1000 U/ML. REPEAT RESULT: 155 U/ML (TESTED WITH AN AUTOMATIC 10 TIMES DILUTION). THE ORIGINAL SAMPLE WAS THEN MANUALLY DILUTED WITH NORMAL SALINE AND OBTAINED THE FOLLOWING REPEAT RESULTS: 73.3 U/ML (TESTED WITH 5 TIMES DILUTION). 13.2 U/ML (TESTED WITH 10 TIMES DILUTION). 3.2 U/ML (TESTED WITH 20 TIMES DILUTION). SINCE THE RESULT DECREASED GRADUALLY WITH THE INCREASE OF THE DILUTION RATIO, THE CUSTOMER SUSPECTED AN INTERFERENCE. THE ORIGINAL SAMPLE WAS ALSO TREATED WITH POLYETHYLENE GLYCOL (PEG) TREATMENT AND THE RESULT WAS 17.88 U/ML.