ELECSYS IGF-1

Description of Event or Problem

WE RECEIVED AN ALLEGATION OF DISCREPANCIES BETWEEN THE ELECSYS IGF-1 MEASUREMENTS FROM THE COBAS E411 ANALYZER WHEN COMPARED WITH THE RESULTS FROM AN IMMULITE 2000XPI SIEMENS HEALTHCARE DIAGNOSTICS ANALYZER, AND WHEN CORRELATED WITH THE CLINICAL COURSE OF SEVERAL PATIENTS FROM A JOURNAL ARTICLE "BEYOND THE METHOD CHANGE IN CLINICAL PRACTICE: EVALUATION OF INSULIN-LIKE GROWTH FACTOR I ASSAY" BY PAULA SIENES BAILO, MARTA FABRE ESTREMERA, JOSÉ CUENCA ALCOCEL, AND MARÍA ÁNGELES CÉSAR MÁRQUEZ, PUBLISHED ONLINE ON 23-AUG 2022. THE JOURNAL ARTICLE IS ATTACHED TO THIS MEDWATCH. THE JOURNAL STATED THAT WITHIN MONTHS AFTER A LABORATORY CHANGED THEIR ASSAY FROM THE IMMULITE 2000XPI, WITH AN ENZYME-LABELLED CHEMILUMINESCENT IMMUNOMETRIC ASSAY LABORATORY METHOD TO THE COBAS E411 WITH AN ELECTROCHEMILUMINESCENCE IMMUNOASSAY LABORATORY METHOD, THEY HAVE OBSERVED A SUSPICIOUSLY HIGH PROPORTION OF SAMPLES WITH IGF-1 CONCENTRATIONS ABOVE THE AGE- AND SEX-SPECIFIC REFERENCE INTERVALS (RIS) PROVIDED BY THE ROCHE DIAGNOSTICS AND THAT CLINICIANS ALSO OBSERVED DISCREPANCIES BETWEEN IGF-1 MEASUREMENTS BY COBAS E411 AND THE CLINICAL COURSE OF SEVERAL PATIENTS; THE IGF-1 RESULTS MEASURED BY THE COBAS E411 WERE GENERALLY HIGHER THAN THOSE OF IMMULITE 2000XPI. THE JOURNAL PROVIDED AN EXAMPLE OF ONE PATIENT WITH DISCREPANT RESULTS FROM THE COBAS (B)(6) ANALYZER. PLEASE REFER TO THE ATTACHMENT (B)(6) IN THE MEDWATCH FOR THE TABLE CONTAINING THE PATIENT'S COMPARISON RESULTS BETWEEN THE TWO ANALYZERS.

Additional Manufacturer Narrative

THE INVESTIGATION IS ONGOING.