ELECSYS CEA

Additional Manufacturer Narrative

THE PATIENT SAMPLE RESULTED IN A CA 19-9 VALUE OF 1222 U/ML AND A CA 125 VALUE OF 23 U/ML. FOR INVESTIGATION, FURTHER EXPERIMENTS WERE PERFORMED WITH THE PATIENT'S SAMPLE ON THE SECOND E 801 ANALYZER. FOR THE FIRST EXPERIMENT, SERUM CONTAINING 997 NG/ML OF CEA WAS ADDED TO THE PATIENT'S SAMPLE IN THE RATIO OF 9:1, INCUBATED, AND THEN MEASURED WITH THE ELECSYS CEA ASSAY. BEFORE ADDING THE SERUM, THE SAMPLE RESULTED IN A CEA VALUE OF 49.8 NG/ML. AFTER ADDING THE SERUM, THE CEA VALUE WAS 98.3 NG/ML, INDICATING A 68 % CEA RECOVERY WHEN COMPARED TO A REFERENCE SAMPLE. FOR THE SECOND EXPERIMENT, A 0.2 M ACETIC ACID SOLUTION (PH 5.0) WAS ADDED TO THE PATIENT SAMPLE, AND HEATED AT 85 DEGREES CELSIUS FOR 10 MINUTES. THE SUPERNATANT WAS SEPARATED AFTER CENTRIFUGATION AND MEASURED WITH THE ELECSYS CEA ASSAY. BEFORE THE ADDITION OF THE ACID, THE SAMPLE WAS DILUTED TIMES 2 AND TESTED, RESULTING IN A CEA VALUE OF 62.6 NG/ML. AFTER THE ADDITION OF THE ACID, THE SAMPLE WAS DILUTED TIMES 2 AND TESTED, RESULTING IN A CEA VALUE OF 83.0 NG/ML. THE CEA RECOVERY WAS 133 % COMPARED TO A REFERENCE SAMPLE. FOR THE THIRD EXPERIMENT, PROTEIN A WAS ADDED TO THE SAMPLE TO REMOVE THE IGG PART OF THE IGM FROM THE SAMPLE. THE SAMPLE WAS ADDED TO MOBI-SPIN COLUMNS FILLED WITH PRE-WASHED PROTEIN A AGAROSE BY AN EQUAL VOLUME AND INCUBATED FOR MORE THAN 3 HOURS AT 2-8 DEGREES CELSIUS WITH ROTATION. THE SAMPLE SUPERNATANT WAS SEPARATED BY CENTRIFUGATION FROM THE SPIN COLUMNS AND MEASURED WITH THE ELECSYS CEA ASSAY. BEFORE TREATMENT, THE SAMPLE RESULTED IN A CEA VALUE OF 49.8 NG/ML. AFTER TREATMENT, THE SAMPLE RESULTED IN A CEA VALUE OF 70.7 NG/MML. THE CEA RECOVERY WAS 142 % COMPARED TO A REFERENCE SAMPLE. THE INVESTIGATION IS ONGOING.

Description of Event or Problem

THE INITIAL REPORTER STATED THEY RECEIVED DISCREPANT RESULTS FOR ONE PATIENT SAMPLE TESTED WITH ELECSYS CEA ON TWO COBAS E 801 MODULE ANALYZERS. THE SAMPLE INITIALLY RESULTED IN A CEA VALUE OF 41.7 NG/ML AND IT REPEATED WITH A VALUE OF 44.3 NG/ML. THE SAMPLE WAS DILUTED 1:2 AND REPEATED, RESULTING IN A VALUE OF 58 NG/ML. THE SAMPLE WAS DILUTED 1:5 AND REPEATED, RESULTING IN A VALUE OF 77.1 NG/ML. THE SAMPLE WAS DILUTED 1:10 AND REPEATED, RESULTING IN A VALUE OF 89.1 NG/ML. THE SAMPLE WAS PROVIDED FOR INVESTIGATION, WHERE IT WAS TESTED ON A SECOND E 801 ANALYZER ON 23-DEC-2024, RESULTING IN A CEA VALUE OF 49.8 NG/ML. THE SAMPLE WAS DILUTED 1:2 AND REPEATED, RESULTING IN A VALUE OF 62.6 NG/ML. THE SAMPLE WAS DILUTED 1:10 AND REPEATED, RESULTING IN A VALUE OF 90.6 NG/ML. THE SAMPLE WAS DILUTED 1:100 AND REPEATED, RESULTING IN A VALUE OF 99.1 NG/ML.

Additional Manufacturer Narrative

CALIBRATION AND CONTROLS WERE ACCEPTABLE. THE INVESTIGATION IS ONGOING.

Additional Manufacturer Narrative

A GENERAL REAGENT ISSUE IS NOT PRESENT AS THE CONTROLS RUN PRIOR TO THE EVENT WERE WITHIN RANGE. PER PRODUCT LABELING, "SAMPLES WITH CEA CONCENTRATIONS ABOVE THE MEASURING RANGE CAN BE DILUTED WITH DILUENT UNIVERSAL. THE RECOMMENDED DILUTION IS 1:50 (EITHER AUTOMATICALLY BY THE ANALYZER OR MANUALLY). THE CONCENTRATION OF THE DILUTED SAMPLE MUST BE = 20 NG/ML." THE INVESTIGATION DETERMINED THAT THE DILUTION RESULT INCREASE UPON 1:2 DILUTION CAN BE CONSIDERED AS A SLIGHT NON-LINEARITY, BUT NOT AS AN INTERFERENCE. THE INVESTIGATION COULD NOT IDENTIFY A PRODUCT PROBLEM.