BEUDAMED
    FDA Adverse Event Malfunction Summary report: N

    MLH1 (M1) MM PAB

    MDR report key: 25096754 · Received May 6, 2026

    Report

    Report Number
    2028492-2026-01765
    Event Type
    Malfunction
    Date Received
    May 6, 2026
    Date of Event
    April 14, 2026
    Report Date
    May 6, 2026
    Manufacturer
    VENTANA MEDICAL SYSTEMS INC.
    Product Code
    PZJ
    PMA / PMN Number
    EXPORT ONLY
    Product Problem
    Yes
    Report Source
    Manufacturer report
    Reporter Location
    SP
    Reporter Occupation
    OTHER HEALTH CARE PROFESSIONAL
    Health Professional
    Yes

    Narratives

    Additional Manufacturer Narrative · 0

    THE SERIAL NUMBER OF THE ANALYZER IS (B)(6). THE CUSTOMER CONFIRMED ISSUES DURING THE PRE-ANALYTICAL PHASE, SPECIFICALLY REGARDING IMPROPER SAMPLE FIXATION FOR PATIENT 1'S SLIDES. THE INVESTIGATION IS ONGOING.

    Description of Event or Problem · 0

    THERE WAS AN ALLEGATION OF QUESTIONABLE RESULTS WITH THE PMS2 (A16-4) MM PAB AND MLH1 (M1) MM PAB ASSAYS FOR TWO PATIENT SAMPLES TESTED ON A BENCHMARK ULTRA PLUS INSTRUMENT. THIS MEDWATCH WILL APPLY TO THE MLH1 (M1) MM PAB ASSAY. PLEASE REFER TO THE MEDWATCH WITH A1. PATIENT IDENTIFIER (B)(6) FOR INFORMATION RELATED TO THE PMS2 (A16-4) MM PAB ASSAY. PATIENT 1: THE STAINING RESULTS WERE POSITIVE FOR PMS2 AND MLH1. THE STAINING RESULTS AT A DIFFERENT LAB WERE NEGATIVE. PATIENT 2: THE STAINING RESULTS WERE NEGATIVE FOR PMS2 AND MLH1. THE REPEAT STAINING RESULT WAS POSITIVE FOR PMS2. THE TESTS WERE REPEATED BECAUSE THE PATHOLOGIST REVIEWED THE SAMPLES AGAIN AND DETERMINED THAT THE STAINING WAS AMBIGUOUS AND THEY SHOULD BE CLASSIFIED AS "UNINTERPRETABLE/UNVALUABLE."

    Devices

    Seq Brand Generic Product Code Manufacturer Model Lot UDI-DI
    447715 MLH1 (M1) MM PAB IMMUNOHISTOCHEMISTRY TEST, DNA MISMATCH REPAIR (MMR) PROTEIN ASSAY PZJ VENTANA MEDICAL SYSTEMS INC. N03791

    Patients

    Seq Age Sex Outcome Treatment
    1