ELECSYS PROBNP II IMMUNOASSAY

Additional Manufacturer Narrative

THE INVESTIGATION IS CURRENTLY ONGOING. THE EVENT OCCURRED IN: (B)(6).

Description of Event or Problem

THE INITIAL REPORTER COMPLAINED OF A POSSIBLE INTERFERANT AFFECTING THE RESULTS OF 2 PATIENT SAMPLES TESTED FOR ELECSYS PROBNP II IMMUNOASSAY ON A COBAS 6000 E 601 MODULE. THE CUSTOMER ONLY PROVIDED SPECIFIC INFORMATION/DATA FOR 1 PATIENT. THE CUSTOMER SUSPECTS THE PATIENT HAS A VARIANT GENE OF PROBNP. THE INITIAL PROBNP RESULT WAS < 5 PG/ML. THE CUSTOMER RETESTED THE SAME PATIENT SAMPLE TWO MORE TIMES, ALL RESULTS WERE < 5 PG/ML. THE ABOVE THREE RESULTS WERE FROM A "HEPARINATED TUBE". THE CUSTOMER ALSO TESTED A SAMPLE THAT WAS COLLECTED IN AN EDTA TUBE AND STATED THE RESULT WAS THE SAME. NO SPECIFIC VALUE PROVIDED. THE RESULTS IN QUESTION WERE REPORTED OUTSIDE OF THE LABORATORY. THE COBAS E601 SERIAL NUMBER WAS (B)(4).

Additional Manufacturer Narrative

MEDWATCH FIELD OTHER RELEVANT HISTORY HAS BEEN UPDATED. THE CUSTOMER STATED THEY HAVE ENCOUNTERED A 3RD PATIENT WITH PROBNP RESULTS OF < 5 PG/ML. THE INVESTIGATION IS ONGOING.

Additional Manufacturer Narrative

TWO OF THE PATIENT SAMPLES WERE SENT TO THE MANUFACTURER FOR INVESTIGATION. THE CUSTOMER¿S RESULT WAS CONFIRMED BY R&D MEASUREMENTS: NT-PROBNP IN THE COMPLAINT SAMPLES WAS NOT DETECTED BY THE ELECSYS PROBNP II ASSAY (SALES LOT < 5 PG/ML). IN ADDITION, THE PATIENT SAMPLES WERE TESTED WITH A MODIFIED PROBNP II ASSAY THAT SHOWS HIGH BIOTIN TOLERANCE UP TO 3500 NG/ML BIOTIN. USING THIS BIOTIN-RESISTANT PROBNP II ASSAY, NT-PROBNP VALUES OF < 5 PG/ML WERE OBTAINED. HENCE, BIOTIN INTERFERENCE IN THE SAMPLES CAN BE EXCLUDED. TWO POINT MUTATIONS IN THE EPITOPE OF THE DETECTION ANTIBODY HAVE BEEN REPORTED. STUDIES OF THE PATIENT SAMPLES DETERMINED NEITHER SAMPLE CONTAINS EITHER POINT MUTATION. THE INVESTIGATION WAS UNABLE TO IDENTIFY THE CAUSE OF THE EVENT. NO PRODUCT PROBLEM WAS FOUND.