TINA-QUANT ANTISTREPTOLYSIN O

Additional Manufacturer Narrative

THE COBAS C 503 ANALYTICAL UNIT SERIAL NUMBER IS (B)(6). THE INVESTIGATION IS ONGOING.

Description of Event or Problem

THE INITIAL REPORTER RECEIVED QUESTIONABLE TINA-QUANT ANTISTREPTOLYSIN O RESULTS FROM ONE PATIENT SAMPLE TESTED ON THE COBAS C 503 ANALYTICAL UNIT. ON (B)(6) 2025: THE INITIAL RESULT OF THE UNDILUTED PATIENT SAMPLE WAS 295 OR 296 IU/ML. THE FIRST REPEAT RESULT OF THE UNDILUTED PATIENT SAMPLE WAS 295 IU/ML. ON (B)(6) 2025: THE SECOND REPEAT RESULT OF THE UNDILUTED PATIENT SAMPLE WAS 308 IU/ML. THE THIRD REPEAT RESULT OF THE UNDILUTED PATIENT SAMPLE WAS 310 IU/ML. THE FOURTH REPEAT RESULT FROM THE FIRST MODULE, WITH THE PATIENT SAMPLE AT 1:5 DILUTION MANUALLY ORDERED, WAS 6504 IU/ML WITH AN INVALIDATING DATA FLAG. THE FIFTH REPEAT RESULT FROM THE FIRST MODULE, WITH THE PATIENT SAMPLE AT 1:5 DILUTION MANUALLY ORDERED, WAS 7895 IU/ML WITH AN INVALIDATING DATA FLAG. THE SIXTH REPEAT RESULT FROM THE SECOND MODULE, WITH HE PATIENT SAMPLE AT 1:3 DILUTION MANUALLY ORDERED, WAS 3445 IU/ML WITH AN INVALIDATING DATA FLAG. THE SEVENTH REPEAT RESULT FROM THE SECOND MODULE, WITH THE PATIENT SAMPLE AT 1:3 DILUTION MANUALLY ORDERED, WAS 7926 IU/ML WITH AN INVALIDATING DATA FLAG. THE EIGHTH REPEAT RESULT FROM A PARTNER LABORATORY'S C 702 MODULE, WITH THE PATIENT SAMPLE UNDILUTED, WAS 257 IU/ML WITH AN INVALIDATING DATA FLAG. THE NINTH REPEAT RESULT FROM THE PARTNER LABORATORY'S C 702 MODULE WITH THE PATIENT SAMPLE ON AUTO RERUN AT DECREASED MODE WAS 7301 IU/ML WITH AN INVALIDATING DATA FLAG. THE TENTH REPEAT RESULT FROM A PARTNER LABORATORY'S C 702 MODULE WITH THE PATIENT SAMPLE AT A 1:50 MANUALLY ORDERED DILUTION WAS 16445 IU/ML. THE PHYSICIAN QUESTIONED THE INITIAL RESULT, AS THE PATIENT'S PREVIOUS RESULTS WERE >6000 IU/ML.

Additional Manufacturer Narrative

MEDWATCH FIELDS A2 AGE NUMBER AND A2 AGE UNITS WERE UPDATED. ABNORMAL ASPIRATION ERRORS WERE ALSO NOTED IN THE ALARM TRACE. PER PRODUCT LABELING, "HIGH-DOSE HOOK EFFECT: NO FALSE RESULT OCCURS UP TO AN ANTISTREPTOLYSIN O ACTIVITY OF 4000 IU/ML." THE INVESTIGATION DETERMINED THAT THE ROOT CAUSE IS RELATED TO A HIGH DOSE HOOK EFFECT, WHICH IS CONSISTENT WITH THE CONCENTRATION IN THE SAMPLE BEING EXTREMELY HIGH.