ELECSYS CMV IGM

Description of Event or Problem

THE INITIAL REPORTER COMPLAINED OF DISCREPANT NEGATIVE RESULTS FOR 1 PATIENT SAMPLE TESTED FOR ELECSYS CMV IGG (CMV IGG) AND ELECSYS CMV IGM (CMV IGM) ON A COBAS E 801 MODULE. THIS MEDWATCH WILL COVER CMV IGM. REFER TO MEDWATCH WITH A1 PATIENT IDENTIFIER (B)(6). FOR INFORMATION ON THE CMV IGG RESULTS. THE CMV IGM RESULT FROM THE E801 MODULE WAS 0.635 COI (NEGATIVE). THE CMV IGG RESULT FROM THE E801 MODULE WAS 0.408 U/ML (NEGATIVE). THE SAMPLE WAS REPEATED BY THE CHORUS METHOD AND THE RESULTS WERE POSITIVE. THE SPECIFIC RESULTS WERE NOT PROVIDED. NO QUESTIONABLE RESULTS WERE REPORTED OUTSIDE OF THE LABORATORY. THE E801 MODULE SERIAL NUMBER WAS (B)(6).

Additional Manufacturer Narrative

THE SAMPLE WAS REQUESTED FOR INVESTIGATION.

Additional Manufacturer Narrative

FOR PCR TESTING, REAL-TIME TAQMAN PROBES AND THERMOCYCLER BIO-RAD CFX 96 WERE USED. FURTHER INVESTIGATIONS PERFORMED WITH THE PATIENT SAMPLES DETERMINED THAT AN ACUTE PRIMARY INFECTION IN THE EARLY PHASE IS INDICATED FOR THE PATIENT. DETECTION OF A SEROCONVERSION TO IGG WAS DELAYED WITH THE ELECSYS CMV IGG ASSAY COMPARED TO OTHER METHODS. EPITOPES REQUIRED FOR THE DETECTION OF THIS RARE SAMPLE ARE NOT SUFFICIENTLY REPRESENTED IN THE ELECSYS CMV IGG ASSAY. BASED ON THE SENSITIVITY CLAIMS FOR THE ELECSYS CMV IGM ASSAY, SINGLE FALSE NEGATIVES CAN OCCUR. THE REAGENT PERFORMS WITHIN SPECIFICATIONS.

Additional Manufacturer Narrative

TWO SAMPLES FROM THE PATIENT WERE PROVIDED FOR INVESTIGATION. THE INVESTIGATION COULD REPRODUCE THE RESULTS OBTAINED BY THE CUSTOMER.

Additional Manufacturer Narrative

FOR THE TWO SAMPLES PROVIDED FOR INVESTIGATION, THE FIRST SAMPLE WAS THE COMPLAINED SAMPLE. THIS SAMPLE HAD A SLIGHTLY POSITIVE CMV PCR RESULT AT 150 COPIES. THE SECOND SAMPLE PROVIDED FOR INVESTIGATION WAS INITIALLY TESTED BY THE CUSTOMER ON (B)(6) 2023. THIS SAMPLE RESULTED IN A CMV IGM VALUE OF 1.06 COI (POSITIVE) AND A CMV IGG VALUE OF 0.417 U/ML (NEGATIVE). ON (B)(6) 2023, THE PATIENT WAS MEASURED USING THE CMV PCR METHOD AND THE RESULT WAS POSITIVE WITH 50 COPIES. A THIRD SAMPLE COLLECTED FROM THE SAME PATIENT AND TESTED ON (B)(6) 2023 RESULTED IN A TOXO IGM VALUE OF 0.207 COI. THIS SAMPLE HAD A POSITIVE CMV PCR RESULT AT 50 COPIES.