IMMULITE 2000 THYROGLOBULIN

Description of Event or Problem

DISCORDANT, FALSELY ELEVATED THYROGLOBULIN (TG) RESULTS WERE OBTAINED ON SAMPLES FROM ONE PATIENT ON THE IMMULITE 2000 INSTRUMENT. THE DISCORDANT RESULT FROM (B)(6) 2012 WAS REPORTED TO THE PHYSICIAN, WHO QUESTIONED THE RESULT. THE SAMPLE WAS THEN TESTED WITH HETEROPHILIC ANTIBODIES, WHICH WERE PRESENT. THE SAMPLE WAS RETESTED WITH AN ALTERNATIVE METHOD, AND THE CORRECT RESULT WAS REPORTED TO THE PHYSICIAN. THE CORRECT RESULT AND CONFIRMATION OF HETEROPHILIC ANTIBODY PRESENCE CAUSED THE PHYSICIAN TO QUESTION PRIOR TG RESULTS FROM THAT PATIENT. TG LEVELS HAD BEEN TESTED AFTER THE PATIENT UNDERWENT A TOTAL THYROIDECTOMY IN SEPTEMBER 2008, AND SEVERAL DISCORDANT RESULTS WERE OBTAINED BETWEEN OCTOBER 2008 AND (B)(6) 2012. SIEMENS RECEIVED THE PATIENT'S HISTORIC RESULTS FROM 2008 AND 2009 ON (B)(6) 2012.

Additional Manufacturer Narrative

THE CUSTOMER CALLED THE SIEMENS TECHNICAL SOLUTIONS CENTER (TSC) TO REPORT THE DISCORDANT RESULT FROM (B)(6) 2012. THE CUSTOMER STATED THAT THE RESULT DID NOT MATCH THE CLINICAL PICTURE, AND ASKED THE LABORATORY TO TEST FOR HETEROPHILIC ANTIBODIES. THE LABORATORY DISCOVERED THAT THE SAMPLE DID CONTAIN HETEROPHILIC ANTIBODIES, WHICH WERE POTENTIALLY INTERFERING WITH THE TG ASSAY. AS PER THE INSTRUCTIONS FOR USE FOR IMMULITE 2000 THYROGLOBULIN, "HETEROPHILIC ANTIBODIES IN HUMAN SERUM CAN REACT WITH THE IMMUNOGLOBULINS INCLUDED IN THE ASSAY COMPONENTS CAUSING INTERFERENCE WITH IN VITRO IMMUNOASSAYS". THE SAMPLE WAS THEN RUN WITH AN ALTERNATE METHOD OF TESTING, THE ULTRASENSITIVE ELISA, TO OBTAIN THE CORRECT RESULT. THE CUSTOMER INDICATED THAT THE CORRECT RESULT AND KNOWLEDGE THAT HETEROPHILIC ANTIBODIES WERE PRESENT CAUSED PRIOR TG RESULTS FROM THE PATIENT TO BE QUESTIONED. POTENTIALLY DISCORDANT RESULTS WERE OBTAINED FROM SAMPLES FROM THAT PATIENT SINCE OCTOBER 2008, WHICH CONTRIBUTED TO THE DECISION FOR THE PATIENT TO HAVE LYMPH NODE CLEARANCE SURGERY. THE HISTORY OF RESULTS WAS PROVIDED TO SIEMENS ON (B)(6) 2012. THE CAUSE OF THE DISCORDANT RESULTS IS UNKNOWN. SIEMENS HAS REQUESTED THE PATIENT SAMPLE FOR TESTING. THE INSTRUMENT IS PERFORMING WITHIN SPECIFICATIONS. NO FURTHER EVALUATION OF THIS ISSUE IS REQUIRED.