N LATEX FLC KAPPA

Additional Manufacturer Narrative

AN OUTSIDE OF THE UNITED STATES (OUS) CUSTOMER CONTACTED A SIEMENS CUSTOMER CARE CENTER (CCC). QUALITY CONTROLS (QC) RECOVERED IN RANGE AND NO INSTRUMENT ERRORS WERE OBSERVED. SIEMENS IS INVESTIGATING THE ISSUE. MDRS 9610806-2022-00015 AND 9610806-2022-00016 WERE FILED FOR THE DISCORDANT FLC KAPPA RESULTS OBTAINED ON (B)(6) 2022 AND (B)(6) 2022, RESPECTIVELY.

Description of Event or Problem

A DISCORDANT, FALSELY LOW FREE LIGHT CHAINS, TYPE KAPPA RESULT WAS OBTAINED ON A PATIENT SAMPLE USING A 1:100 SAMPLE DILUTION ON AN ATELLICA NEPH 630 SYSTEM USING N LATEX FLC KAPPA REAGENT. THE SAMPLE WAS THEN REPEATED FOR FLC KAPPA USING A 1:2000, 1:8000, AND 1:32000 SAMPLE DILUTION, EACH TIME RECOVERING FALSELY LOW. THE SAMPLE WAS REMEASURED FOR FLC KAPPA THE FOLLOWING DAY USING A 1:100 SAMPLE DILUTION, ALSO RECOVERING FALSELY LOW. THE DISCORDANT RESULTS WERE NOT REPORTED TO THE PHYSICIAN(S) AS A HIGHER RESULT WAS EXPECTED DUE TO THE PRESENCE OF AN M-COMPONENT KAPPA BAND IN THE PATIENT'S ELECTROPHORESIS RESULT. EIGHTEEN DAYS LATER, A NEW SAMPLE FROM THE SAME PATIENT WAS MEASURED FOR FLC KAPPA FOUR TIMES USING A 1:5, 1:20, 1:100, AND 1:32000 SAMPLE DILUTION, EACH TIME RECOVERING FALSELY LOW. THE DISCORDANT RESULTS WERE NOT REPORTED TO THE PHYSICIAN(S). THERE ARE NO KNOWN REPORTS OF PATIENT INTERVENTION OR ADVERSE HEALTH CONSEQUENCES DUE TO THE FALSELY LOW FLC KAPPA RESULTS.

Additional Manufacturer Narrative

SIEMENS FILED THE INITIAL MDR 9610806-2022-00017 ON 04-APR-2022. ADDITIONAL INFORMATION (11-APR-2022): NO SYSTEM DATA FILES WERE PROVIDED FROM THE DATE OF EVENT, SO THE KINETICS OF THE SAMPLE MEASUREMENTS COULD NOT BE ANALYZED. THE ISSUE WAS LIMITED TO SAMPLES FROM ONE PATIENT. AS PER THE INSTRUCTIONS FOR USE (IFU) FOR N LATEX FLC KAPPA, "PATIENT SAMPLES MAY CONTAIN HETEROPHILIC ANTIBODIES THAT COULD REACT IN IMMUNOASSAYS TO GIVE A FALSELY ELEVATED OR DEPRESSED RESULT. THIS ASSAY HAS BEEN DESIGNED TO MINIMIZE INTERFERENCE FROM HETEROPHILIC ANTIBODIES. NEVERTHELESS, COMPLETE ELIMINATION OF THIS INTERFERENCE FROM ALL PATIENT SPECIMENS CANNOT BE GUARANTEED. EXCESSIVELY ELEVATED MONOCLONAL IMMUNOGLOBULIN CONCENTRATIONS MIGHT HAVE THE POTENTIAL TO SUPPRESS THE REACTION OF ANTI-FLC ANTIBODIES WITH FREE LIGHT CHAIN MOLECULES. IF RESULTS DO NOT FIT TO PREVIOUS ONES, OR TO RESULTS OF OTHER TESTS (E. G. SERUM IMMUNOELECTROPHORESIS, IMMUNOFIXATION, DIFFERENTIAL BLOOD CELL COUNT) AND/OR TO THE CLINICAL SITUATION, IT IS RECOMMENDED TO RE-ANALYZE THE SAMPLE IN A HIGHER SAMPLE DILUTION." THE ISSUE IS SAMPLE SPECIFIC AND THE CAUSE OF THE EVENT IS UNKNOWN. THE REAGENT IS PERFORMING ACCORDING TO SPECIFICATIONS. NO FURTHER EVALUATION OF THIS DEVICE IS REQUIRED. MDRS 9610806-2022-00015_S1 AND 9610806-2022-00016_S1 WERE ALSO FILED FOR THE ADDITIONAL INFORMATION OBTAINED ON 11-APR-2022.