ELECSYS T4 ASSAY

Additional Manufacturer Narrative

TWO SAMPLES FROM THE PATIENT WERE SUBMITTED FOR INVESTIGATION WHERE AN INTERFERING FACTOR AGAINST STREPTAVIDIN WAS CONFIRMED. THIS INTERFERENCE CAUSED THE HIGH FT3 III, T4 AND T3 RESULTS AND THE LOW PTH RESULTS. THIS INTERFERENCE IS ADDRESSED IN PRODUCT LABELING: "IN RARE CASES, INTERFERENCE DUE TO EXTREMELY HIGH TITERS OF ANTIBODIES TO ANALYTE-SPECIFIC ANTIBODIES, STREPTAVIDIN OR RUTHENIUM CAN OCCUR. THESE EFFECTS ARE MINIMIZED BY SUITABLE TEST DESIGN." THE INVESTIGATION DID NOT IDENTIFY A PRODUCT PROBLEM.

Additional Manufacturer Narrative

THE CUSTOMER PERFORMED INTERFERENCE TESTING WITH A HETEROPHILIC BLOCKING TUBE AND POLYETHYLENE GLYCOL (PEG) PRECIPITATION. THE INVESTIGATION IS ONGOING.

Description of Event or Problem

THE INITIAL REPORTER QUESTIONED RESULTS NOT MEETING THE CLINICAL PICTURE FOR 1 PATIENT TESTED FOR ELECSYS T3 (T3), ELECSYS T4 (T4), ELECSYS PTH (PTH), ELECSYS FT3 III (FT3 III) AND ELECSYS T4 (T4) ON 2 COBAS E801 MODULES. THIS MEDWATCH WILL COVER T4. REFER TO MEDWATCH WITH PATIENT IDENTIFIER (B)(6) FOR INFORMATION ON THE PTH RESULTS, MEDWATCH WITH PATIENT IDENTIFIER (B)(6) FOR INFORMATION ON THE T3 RESULTS AND MEDWATCH WITH PATIENT IDENTIFIER (B)(6) FOR INFORMATION ON THE FT3 III RESULTS. DATA WAS PROVIDED FOR 2 SAMPLES FROM THE PATIENT OBTAINED ON (B)(6) 2020 AND (B)(6) 2020. THE E801 MODULE SERIAL NUMBERS WERE(B)(4). THE CUSTOMER SUSPECTS AN ANTIBODY INTERFERENCE. THE PATIENTS PTH RESULTS ARE LOW WITH NO SYMPTOMS OF HYPOPARATHYROIDISM OR ISSUES WITH CA, PO4 OR VITAMIN D RESULTS. THE PATIENTS T3, FT3 III AND T4 RESULTS ARE ELEVATED WITH NO SYMPTOMS OF HYPERTHYROIDISM AND THE PATIENTS TSH AND FT4 II RESULTS WERE NORMAL.