A united states (us) customer contacted the siemens healthcare remote services center (rsc) regarding eight (8) falsely elevated calcium_2 (ca_2) patient sample results obtained on an atellica ch 930 analyzer.Initial mdr 2432235-2024-00005 was filed on 17-jan-2024.Additional information (18-jan-2024): siemens healthcare diagnostics concluded the investigation of the event.Siemens reviewed the instrument data logs, calibration data and the information provided by the customer.Quality control (qc) data showed intermittent out-of-range recovery on the day of the event.Siemens observed variability with the calibration coefficients which was consistent with the variability observed with the qc and falsely elevated patient results.Siemens investigation of the event is consistent with the lot calibration issue and inconsistent calibrator handling/reconstitution.In the absence of instrument related causes, the variability observed with the calibration coefficients across calibration events suggests inconsistent reconstitution/handling of the atellica chemistry calibrator (chem cal) material.Results obtained from calibrators are subject to the same variability or imprecision as qc and patient results.Consequently, the same analyte signal is not achieved every time the calibrators are run.For optimal calibrator performance, siemens recommends the customer review the chem cal instructions for use (ifu) for calibrator handling/reconstitution instruction.Ensure that the chem cal is reconstituted using reagent grade water and a precision pipette.Lyophilized materials such as qc and calibrators will be impacted if the reagent water quality is poor or contaminated.Using incorrect pipettes, inadequate mixing, or failing to ensure homogeneity of the chem cal material are also possible contributing factors.Note: a "pack" calibration performed on the atellica ch instrument is specific to the reagent pack and well that is used to calibrate.Once the instrument moves to a new well of the same reagent pack or a new reagent pack, the instrument will no longer use the pack calibration to process samples.Unless a new "pack calibration" is performed on the new well or pack, then the instrument will process samples using the most recent "lot calibration." based on the information provided and a review of the instrument data, siemens concludes the probable cause of the discrepant ca_2 results, and the out-of-range qc was due to an issue with the lot calibration (cal id 9783) from (b)(6) 2023 used to process the samples in question.There is insufficient information provided for siemens to determine what caused the calibration issue.However, inconsistent calibrator handling/reconstitution cannot be ruled out as a contributing factor.The customer resolved the issue by recalibrating on (b)(6) 2023.No further issues with ca_2 have been observed post calibration.The actions taken by the customer were part of normal troubleshooting/maintenance for issues of this nature.The customer is operational.In section h6, investigation findings and investigation conclusions codes are updated.
|