Additional information (06-oct-2021): siemens headquarters support center (hsc) has concluded the investigation of the event.The customer contacted the siemens healthcare diagnostics customer care center (ccc) regarding a discordant elevated free prostate specific antigen (fpsa) patient sample result obtained on a dimension vista 1500 system.The same patient sample was diluted on (b)(6) 2021 and processed on a dimension vista system.The fpsa results showed the sample did not dilute linearly with the dimension vista fpsa assay which could be a potential indication of non-specific binding interference such as a heterophilic antibody or other autoantibodies.Quality control and calibration were within expectations indicating the assay was working as designed and the issue was specific to the patient.A patient sample was requested for siemens evaluation but none has been provided.The customer has declined to give further history concerning the patient medication and treatment.The interference described matches the presentation of non-specific binding such as seen with heterophilic interference or autoantibodies.This type of interference is known to occur in all forms of immunoassay and the assay instruction for use (ifu) contains the following cautions: "results of this test should always be interpreted in conjunction with the patient's medical history, clinical presentation and other findings." and "patient samples may contain heterophilic antibodies that could react in immunoassays to give falsely elevated or depressed results.This assay has been designed to minimize interference from heterophilic antibodies.Nevertheless, complete elimination of this interference from all patient specimens cannot be guaranteed.A test result that is inconsistent with the clinical picture and patient history should be interpreted with caution." the cause of the issue could be due to a potential patient specific heterophilic antibody interference, however that cannot be confirmed with the available data, therefore, the cause is unknown.The device is performing within specifications.No further evaluation is required.Section h6 has been updated to reflect the hsc investigation.Initial mdr 2517506-2021-00248 was filed 03-sep-2021.
|