N LATEX FLC KAPPA

Additional Manufacturer Narrative

SIEMENS FILED THE INITIAL MDR ON 07-NOV-2019. ADDITIONAL INFORMATION (11-NOV-2019): THE KINETIC DATA FOR THE FLC KAPPA RESULTS COULD NOT BE EVALUATED, AS ALL MEASUREMENTS WERE FOUND BELOW OR ABOVE THE MEASUREMENT RANGE. QUALITY CONTROLS (QC) RECOVERED WITHIN RANGE AT THE TIME OF THE EVENT, INDICATING THAT THE SYSTEM AND REAGENT WERE PERFORMING ACCORDING TO SPECIFICATIONS. THE CAUSE OF THE DISCORDANT RESULT COULD NOT BE DETERMINED. HOWEVER, SAMPLE INTEGRITY OR OTHER PREANALYTICAL VARIABLES COULD NOT BE RULED OUT AS CONTRIBUTING FACTORS. AS PER THE INSTRUCTIONS FOR USE (IFU) FOR N LATEX FLC KAPPA "EXCESSIVELY ELEVATED MONOCLONAL IMMUNOGLOBULIN CONCENTRATIONS MIGHT HAVE THE POTENTIAL TO SUPPRESS THE REACTION OF ANTI-FLC ANTIBODIES WITH FREE LIGHT CHAIN MOLECULES. IN ADDITION, OTHER CONDITIONS MAY CAUSE LOWER FLC CONCENTRATIONS, E.G., BI-CLONAL AFTER THERAPY, POLYMERIZATION OF LAMBDA CHAINS, ETC. IF RESULTS DO NOT FIT TO PREVIOUS ONES, OR TO RESULTS OF OTHER TESTS (E.G., SERUM AND URINE PROTEIN ELECTROPHORESIS, IMMUNOFIXATION, DIFFERENTIAL BLOOD CELL COUNT) AND/OR TO THE CLINICAL SITUATION, IT IS RECOMMENDED TO RE-ANALYZE THE SAMPLE IN A HIGHER SAMPLE DILUTION. SUCH SAMPLES MAY ALSO NOT DILUTE IN A LINEAR FASHION." THE REAGENT IS PERFORMING ACCORDING TO SPECIFICATIONS. NO FURTHER EVALUATION OF THIS DEVICE IS REQUIRED.

Additional Manufacturer Narrative

THE CUSTOMER CONTACTED A SIEMENS CUSTOMER CARE CENTER (CCC) AND REPORTED THAT A DISCORDANT, FALSELY LOW FREE LIGHT CHAIN (FLC) KAPPA RESULT WAS OBTAINED ON A PATIENT SERUM SAMPLE ON A BN PROSPEC SYSTEM USING N LATEX FLC KAPPA REAGENT. SIEMENS IS INVESTIGATING THE ISSUE.

Description of Event or Problem

A DISCORDANT, FALSELY LOW FREE LIGHT CHAIN (FLC) KAPPA RESULT WAS OBTAINED ON A PATIENT SERUM SAMPLE ON A BN PROSPEC SYSTEM USING N LATEX FLC KAPPA REAGENT. THE RESULT WAS REPORTED TO THE PHYSICIAN(S) AND WAS QUESTIONED BY THE PHYSICIAN(S). THE SAME SAMPLE WAS RERUN FOR FLC KAPPA ON A DIFFERENT DATE, RESULTING HIGHER. A SECOND SAMPLE FROM THE SAME PATIENT WAS RUN FOR FLC KAPPA, ALSO RESULTING HIGHER AND CONFIRMING THE REPEAT RESULT. THE REPEAT RESULTS WERE REPORTED, AS THE CORRECT RESULTS, TO THE PHYSICIAN(S). THERE ARE NO REPORTS OF PATIENT INTERVENTION OR ADVERSE HEALTH CONSEQUENCES DUE TO THE DISCORDANT, FALSELY LOW FLC KAPPA RESULT.