MAUDE Adverse Event Report: SIEMENS HEALTHCARE DIAGNOSTICS PRODUCTS GMBH COAGULATION FACTOR VIII DEFICIENT PLASMA; PLASMA, COAGULATION FACTOR DEFICIENT

Catalog Number	10445729
Medical Device Problem Code	High Test Results (2457)
Health Effect - Clinical Code	No Clinical Signs, Symptoms or Conditions (4582)
Date of Event	09/29/2025
Type of Reportable Event	Malfunction
Additional Manufacturer Narrative
An outside of the united states (ous) customer contacted the siemens customer care center to report discordant elevated coagulation factor viii / dade actin fs activated ptt reagent results that were obtained on one patient sample on the cs-2500 instrument.The following conclusion is made by siemens healthineers: the issue is caused by a known interferent from the medication (emicizumab) as this leads to elevated results with one-stage clotting assays (aptt and aptt based fviii determination).This is a well-known and generic interference based on assay principles.The dramatic shortening of aptt caused by emicizumab leads to significant interference with the one-stage fviii activity assay.This phenomenon has been thoroughly described in studies such as 'laboratory monitoring in emicizumab-treated persons with hemophilia a' and 'effects and interferences of emicizumab, a humanised bispecific antibody mimicking activated factor viii cofactor function, on coagulation assays', both available on pubmed." emicizumab does not interfere with the siemens coagulation factor viii / factor viii chromogenic assay.No fviii activity is exhibited by emicizumab using the siemens chromogenic assay.This fits to customer observation.Obtained result for sample of a patient with severe hemophilia a treated with emicizumab.According to complaint description remaining fviii activity is ~1%.The aptt based fviii determination showed a highly overestimated result due to interference of emicizumab.
Event or Problem Description
The customer reported the observation of discordant increased results of coagulation factor viii / dade actin fs activated ptt reagent assay for one patient with known hemophilia a on the cs-2500 system using aptt with factor viii.The sample was repeated with an alternate method siemens coagulation factor viii / factor viii chromogenic assay and recovered lower.There are no known reports of patient intervention or adverse health consequences due to the discordant result.

• Brand Name: COAGULATION FACTOR VIII DEFICIENT PLASMA
• Common Device Name: PLASMA, COAGULATION FACTOR DEFICIENT
• Manufacturer (Section D): SIEMENS HEALTHCARE DIAGNOSTICS PRODUCTS GMBH; emil-von-behring- str. 76; marburg 35041 ; GM 35041
• Manufacturer (Section G): SIEMENS HEALTHCARE DIAGNOSTICS PRODUCTS GMBH; emil-von-behring- str. 76; marburg 35041 ; GM 35041
• Manufacturer Contact: michael bloecher ; emil-von-behring- str. 76; marburg 35041 ; GM 35041
• MDR Report Key: 23377292
• Report Number: 9610806-2025-00050
• Device Sequence Number: 8871850
• Product Code: GJT
• UDI-Device Identifier: 00842768004032
• UDI-Public: 00842768004032
• Combination Product (Y/N): N
• Initial Reporter Country: NZ
• PMA/510(K) Number: K924396
• Number of Events Summarized: 1
• Summary Report (Y/N): N
• Serviced by Third Party (Y/N): N
• Reporter Type: Manufacturer
• Report Source: Foreign,Health Professional,User Facility
• Initial Reporter Occupation: Other Health Care Professional
• Type of Report: Initial
• Report Date (Section B): 10/24/2025

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: 10445729
• Device Lot Number: NOT PROVIDED
• Was Device Available for Evaluation?: No
• Is the Reporter a Health Professional?: Yes
• Type of Report(Section G): Thirty-Day
• Initial Date Received by Manufacturer: 09/30/2025
• Initial Report FDA Received Date: 10/24/2025
• Was Device Evaluated by Manufacturer? (Y/N): No
• Is the Device Labeled for Single Use? (Y/N): No
• Usage of Device: Initial
• Patient Sequence Number: 1
• Patient Age: 9 YR
• Patient Sex: Male