ELECSYS HTLV-I/II

Description of Event or Problem

WE RECEIVED AN ALLEGATION OF AN INCREASE IN REACTIVE ELECSYS HTLV-I/II ASSAY RESULTS OVER A 10-DAY PERIOD. THESE RESULTS WERE ASSOCIATED WITH BLOOD BANK DONOR SAMPLES TESTED ON THE COBAS E 411 ANALYZER (RACK SYSTEM). THE DONORS ALLEGEDLY HAVE NO HISTORY OF HUMAN T-LYMPHOTROPIC VIRUS (HTLV) INFECTION. THE FOLLOWING PATIENT SAMPLES WITH QUESTIONABLE RESULTS WERE PROVIDED: PATIENT SAMPLE 1: THE INITIAL RESULT USING THE DONOR'S SAMPLE TUBE WAS 5.7 COI (REACTIVE). THE REPEAT RESULT USING THE DONOR'S SAMPLE TUBE WAS 5.74 COI (REACTIVE). THE REPEAT RESULT USING THE SAMPLE FROM THE DONOR'S BLOOD BAG WAS 4.24 COI (REACTIVE). PATIENT SAMPLE 2: THE INITIAL RESULT USING THE DONOR'S SAMPLE TUBE WAS 1.16 COI (REACTIVE). THE REPEAT RESULT USING THE DONOR'S SAMPLE TUBE WAS 1.17 COI (REACTIVE). THE REPEAT RESULT USING THE SAMPLE FROM THE DONOR'S BLOOD BAG WAS 1.2 COI (REACTIVE). PATIENT SAMPLE 3: THE INITIAL RESULT USING THE DONOR'S SAMPLE TUBE WAS 1.30 COI (REACTIVE). THE REPEAT RESULT USING THE DONOR'S SAMPLE TUBE WAS 1.34 COI (REACTIVE). THE REPEAT RESULT USING THE SAMPLE FROM THE DONOR'S BLOOD BAG WAS 1.14 COI (REACTIVE). PATIENT SAMPLE 4: THE INITIAL RESULT USING THE DONOR'S SAMPLE TUBE WAS 1.01 COI (REACTIVE). THE REPEAT RESULT USING THE DONOR'S SAMPLE TUBE WAS 0.21 COI (NON-REACTIVE). THE REPEAT RESULT USING THE SAMPLE FROM THE DONOR'S BLOOD BAG WAS 0.22 COI (NON-REACTIVE).

Additional Manufacturer Narrative

THE COBAS E 411 ANALYZER (RACK SYSTEM) SERIAL NUMBER IS (B)(6). PRODUCT LABELING STATES: "ALL INITIALLY REACTIVE SAMPLES SHOULD BE REDETERMINED IN DUPLICATE WITH THE ELECSYS HTLV-I/II ASSAY. IF CUTOFF INDEX VALUES < 1.00 ARE FOUND IN BOTH CASES, THE SAMPLES ARE CONSIDERED NEGATIVE FOR HTLV-SPECIFIC ANTIBODIES. INITIALLY REACTIVE SAMPLES GIVING CUTOFF INDEX VALUES OF = 1.00 IN EITHER OF THE REDETERMINATIONS ARE CONSIDERED REPEATEDLY REACTIVE. REPEATEDLY REACTIVE SAMPLES MUST BE CONFIRMED ACCORDING TO RECOMMENDED CONFIRMATORY ALGORITHMS. CONFIRMATORY TESTS INCLUDE WESTERN LOT AND HTLV PCR TESTS." "FOR DIAGNOSTIC PURPOSES, THE RESULTS SHOULD ALWAYS BE ASSESSED IN CONJUNCTION WITH THE PATIENT¿S MEDICAL HISTORY, CLINICAL EXAMINATION AND OTHER FINDINGS." THE INVESTIGATION IS ONGOING.