MAUDE Adverse Event Report: VENTANA MEDICAL SYSTEMS INC. BENCHMARK ULTRA SYSTEM; SLIDE STAINER, AUTOMATED

Catalog Number	05342716001
Medical Device Problem Code	Incorrect, Inadequate or Imprecise Result or Readings (1535)
Health Effect - Clinical Code	No Clinical Signs, Symptoms or Conditions (4582)
Date of Event	12/09/2025
Type of Reportable Event	Malfunction
Additional Manufacturer Narrative
The investigation is ongoing.
Event or Problem Description
There was an allegation of discrepant staining results for several patient samples tested on different benchmark ultra systems.The customer is experiencing significant inter-instrument variability across 6 different benchmark ultra systems.The same control tissue showed different staining patterns on each system.Some systems produce unexpected variations in staining intensity (weaker vs.Stronger signal), while others exhibit issues with homogeneity (patchy or uneven staining) on the same tissue structures.
Additional Manufacturer Narrative
The field service engineer (fse) went on site and identified improper reaction buffer dispensing on one instrument (sn (b)(6)) and minor mechanical adjustments needed on a second (sn (b)(6)).Decontamination was also performed on a third instrument (sn (b)(6)).It was observed that the rinse valve was not dispensing consistent volumes and contamination in the associated reagent reservoir was detected for sn (b)(6).An fse replaced the valve and filters due to the contamination with a comment to also follow up with routine decontamination.No other issues were found for the remaining 3 instruments.The investigation was not able to identify a singular root cause.The probable contributing factors include instrument contamination (apparent on at least two instruments) and pre-analytic handling (e.G.Slide handling and tissue placement).The benchmark ultra vss software schedules decontamination of the instrument bulk bottles, reservoirs, and fluidic system every 90 days (an icon appears to alert/remind users).Per the operator's manual, the 20l carboys are also required to be decontaminated every 90 days.

• Brand Name: BENCHMARK ULTRA SYSTEM
• Common Device Name: SLIDE STAINER, AUTOMATED
• Manufacturer (Section D): VENTANA MEDICAL SYSTEMS INC.; 1910 e innovation park dr; tucson AZ 85755
• Manufacturer (Section G): VENTANA MEDICAL SYSTEMS INC.; 1910 e innovation park dr; tucson AZ 85755
• Manufacturer Contact: natalie catton ; 9115 hague road; indianapolis, IN 46250 ; 9253534412
• MDR Report Key: 23992709
• Report Number: 2028492-2026-00088
• Device Sequence Number: 18772476
• Product Code: KPA
• UDI-Device Identifier: 04015630981052
• UDI-Public: 04015630981052
• Combination Product (Y/N): N
• Initial Reporter Country: GM
• PMA/510(K) Number: EXEMPT
• Number of Events Summarized: 1
• Summary Report (Y/N): N
• Serviced by Third Party (Y/N): Unknown
• Reporter Type: Manufacturer
• Report Source: Foreign,Health Professional,User Facility
• Initial Reporter Occupation: Other Health Care Professional
• Type of Report: Initial,Followup
• Report Date (Section B): 04/01/2026

1 Device was Involved in the Event

1 Patient was Involved in the Event

• Is this an Adverse Event Report?: No
• Is this a Product Problem Report?: Yes
• Operator of Device: Health Professional
• Device Catalogue Number: 05342716001
• Was Device Available for Evaluation?: Yes
• Is the Reporter a Health Professional?: Yes
• Type of Report(Section G): Initial
• Initial Date Received by Manufacturer: 12/09/2025
• Supplement Date Received by Manufacturer: 03/09/2026
• Initial Report FDA Received Date: 01/07/2026
• Supplement Report FDA Received Date: 04/01/2026
• Was Device Evaluated by Manufacturer? (Y/N): Yes
• Is the Device Labeled for Single Use? (Y/N): No
• Is This a Single-Use Device that was Reprocessed and Reused on a Patient? (Y/N): No
• Patient Sequence Number: 1
• Patient Sex: Unknown