INNOVANCE VON WILLEBRAND FACTOR ACTIVITY

Additional Manufacturer Narrative

AN OUTSIDE OF THE UNITED STATES (OUS) CUSTOMER CONTACTED A SIEMENS CUSTOMER CARE CENTER (CCC). NO HARDWARE ERROR MESSAGES OCCURRED DURING THE TIME OF THE EVENT. NO SAMPLE OR REAGENT HANDLING ERRORS WERE IDENTIFIED. NO ISSUES WERE OBSERVED WITH THE SAMPLE KINETICS. INTERFERENCE DUE TO HUMAN ANTI-MOUSE ANTIBODIES (HAMA) CANNOT BE RULED OUT AS A POTENTIAL CAUSE OF THE INCONSISTENT RESULTS. AS PER THE INNOVANCE VON WILLEBRAND FACTOR ACTIVITY INSTRUCTIONS FOR USE (IFU): "PATIENT SAMPLES MAY CONTAIN HETEROPHILIC ANTIBODIES (E.G. HUMAN ANTI-MOUSE ANTIBODIES (HAMA) AND RHEUMATOID FACTORS) OR PARAPROTEINS THAT COULD REACT IN TURBIDIMETRIC ASSAYS USING MOUSE MONOCLONAL ANTIBODIES TO GIVE FALSELY ELEVATED OR DEPRESSED RESULTS. THIS ASSAY HAS BEEN DESIGNED TO MINIMIZE INTERFERENCE FROM HETEROPHILIC ANTIBODIES BY ADDITION OF A BLOCKING REAGENT. NO INTERFERENCE OF RHEUMATOID FACTORS (RF) WAS OBSERVED UP TO 940 IU/ML. NEVERTHELESS, COMPLETE ELIMINATION OF THIS INTERFERENCE FROM ALL PATIENT SPECIMENS CANNOT BE GUARANTEED." ADDITIONALLY THE IFU INDICATES: "RESULTS OF THIS TEST SHOULD ALWAYS BE INTERPRETED IN CONJUNCTION WITH THE PATIENT'S MEDICAL HISTORY, CLINICAL PRESENTATION AND OTHER FINDINGS." THE CAUSE OF THE EVENT IS UNKNOWN. THE ATELLICA COAG 360 SYSTEM IS NOT MARKETED IN THE US NOR SIMILAR IN DESIGN TO A SIEMENS PRODUCT REGISTERED IN THE US. THE REAGENT IS PERFORMING ACCORDING TO SPECIFICATIONS. NO FURTHER EVALUATION OF THIS DEVICE IS REQUIRED. MDRS 9610806-2022-00057 AND 9610806-2022-00059 WERE FILED FOR THE DISCORDANT RESULTS OBTAINED ON (B)(6) 2022 AND (B)(6) 2022, RESPECTIVELY.

Description of Event or Problem

A FALSELY LOW VON WILLEBRAND FACTOR ACTIVITY (VWF AC) RESULT WAS OBTAINED ON A PATIENT SAMPLE ON AN ATELLICA COAG 360 SYSTEM USING INNOVANCE VON WILLEBRAND FACTOR ACTIVITY REAGENT. THE DISCORDANT RESULT WAS NOT REPORTED TO THE PHYSICIAN(S). THREE DAYS LATER THE SAMPLE WAS REPEATED FOR VWF AC FOUR TIMES, TWO TIMES USING THE VWF AC LOW SETTING AND TWO TIMES USING THE VWF AC MEDIUM SETTING. THE RESULTS OBTAINED USING THE VWF AC MEDIUM SETTING RECOVERED FALSELY LOW. THE SAMPLE WAS FROZEN AND WAS RERUN FOR VWF AC EIGHTEEN DAYS LATER USING BOTH THE VWF AC LOW SETTING AND THE VWF AC MEDIUM SETTING. THE RESULT OBTAINED USING THE VWF AC MEDIUM SETTING RECOVERED FALSELY LOW. AFTER DILUTING THE SAMPLE 1:2 AND RUNNING THE SAMPLE, A CORRECT NUMERIC VWF AC RESULT WAS OBTAINED USING THE VWF LOW SETTING. THERE ARE NO KNOWN REPORTS OF PATIENT INTERVENTION OR ADVERSE HEALTH CONSEQUENCES DUE TO FALSELY LOW VWF AC RESULTS.