DIMENSION VISTA®

Additional Manufacturer Narrative

THE CUSTOMER CONTACTED SIEMENS HEALTHCARE DIAGNOSTICS CONCERNING THE IMPACT OF BIOTIN ON THE FT4 RESULT ON A PATIENT RECEIVING A DOSAGE OF BIOTIN. THE CAUSE OF THE DISCORDANT ELEVATED FT4 RESULT IS UNKNOWN. QUALITY CONTROL WAS WITHIN SPECIFICATION. MDR 2517506-2017-00552 AND 2517506-2017-00554 WERE FILED FOR THE SAME EVENT. SIEMENS IS INVESTIGATING THE INCIDENT.

Description of Event or Problem

A DISCORDANT ELEVATED FREE THYROXINE (FT4) RESULT WAS OBTAINED ON A PATIENT SAMPLE ON THE DIMENSION VISTA 1500 SYSTEM. THE INITIAL RESULT WAS NOT REPORTED TO THE PHYSICIAN. THE SAME PATIENT SAMPLE WAS TESTED AT AN ALTERNATE FACILITY WITH AN ALTERNATE METHODOLOGY AND A LOWER RESULT WAS OBTAINED. THERE ARE NO REPORTS OF PATIENT INTERVENTION OR ADVERSE HEALTH CONSEQUENCES AS A RESULT OF THE DISCORDANT ELEVATED FT4 RESULT.

Additional Manufacturer Narrative

SIEMENS HEALTHCARE DIAGNOSTICS CONCLUDED THE INVESTIGATION OF POTENTIAL INTERFERENCE OF BIOTIN ON DIMENSION VISTA FT4 RESULTS. THE INSTRUCTIONS FOR USE FOR THE DIMENSION VISTA FT4 FLEX REAGENT CARTRIDGE HAS BEEN REVISED TO INCLUDE IN THE LIMITATIONS OF PROCEDURE SECTION THE FOLLOWING STATEMENT: "SPECIMENS THAT CONTAIN BIOTIN AT A CONCENTRATION OF 100 NG/ML DEMONSTRATE A LESS THAN OR EQUAL TO 10% CHANGE IN RESULTS. BIOTIN CONCENTRATIONS GREATER THAN THIS MAY LEAD TO FALSELY ELEVATED RESULTS FOR PATIENT SAMPLES. RESULTS FROM PATIENTS TAKING BIOTIN SUPPLEMENTS OR RECEIVING HIGH-DOSE BIOTIN THERAPY SHOULD BE INTERPRETED WITH CAUTION DUE TO POSSIBLE INTERFERENCE WITH THIS TEST."

Additional Manufacturer Narrative

THE ORIGINAL MDR 2517506-2017-00553 WAS FILED 7/7/2017. THE FT4 ASSAY HAS BEEN TESTED FOR POTENTIAL INTERFERENCE AT BIOTIN LEVELS OF 100, 250, 500, AND 1200 NG/ML. INTERFERENCE TESTING WAS PERFORMED FOLLOWING CLINICAL LABORATORY STANDARDS INSTITUTE (CLSI) GUIDANCE AT CONCENTRATIONS APPROXIMATELY EQUIVALENT TO THE LEVELS LISTED IN THE IFU. BELOW IS THE BIOTIN INTERFERENCE OF DIMENSION VISTA FT4 TEST LEVEL: 1.4 UNITS: NG/DL BIOTIN TEST LEVEL AND % INTERFERENCE OBSERVED 1200 NG/ML *. 500 NG/ML 37.6%. 250 NG/ML 8.4%. 100 NG/ML 1.5%. *RESULT FOR SAMPLE WITH 1200 NG/ML BIOTIN IS ABOVE THE ANALYTICAL MEASUREMENT RANGE AND PERCENTAGE INCREASE COULD NOT BE CALCULATED. THE SIEMENS INVESTIGATION IS CONTINUING.