TINA-QUANT ANTISTREPTOLYSIN O

Additional Manufacturer Narrative

THE C702 MODULE SERIAL NUMBER WAS (B)(6).

Description of Event or Problem

THE INITIAL REPORTER COMPLAINED OF DISCREPANT RESULTS FOR 1 PATIENT SAMPLE TESTED FOR TINA-QUANT ANTISTREPTOLYSIN O (ASLO TQ) ON A COBAS 8000 C 702 MODULE. THE INITIAL RESULT WITH REAGENT LOT 748374 (EXP. 31-OCT-2024) WAS >549 IU/ML WITH AN INVALIDATING DATA FLAG. THE REPEAT RESULT USING THE SAME REAGENT LOT WITH A 1:10 DILUTION WAS >6797 IU/ML WITH AN INVALIDATING DATA FLAG. THE SAMPLE WAS REPEATED WITH A 1:20 DILUTION WITH REAGENT LOT 760770 AND THE RESULT WAS 49 IU/ML. THE PATIENT WAS TESTED IN A DIFFERENT LABORATORY AND THE RESULT WAS "ALMOST 6000." THE SAMPLE WAS REPEATED WITH A 1:20 DILUTION WITH REAGENT LOT 760770 AND THE RESULT WAS >13782 IU/ML WITH AN INVALIDATING DATA FLAG. THE SAMPLE WAS REPEATED WITH A 1:50 DILUTION USING THE SAME REAGENT LOT AND THE RESULT WAS 13411 IU/ML.

Additional Manufacturer Narrative

CALIBRATION WAS ACCEPTABLE. QC SHOWED IMPRECISION WITH LOW RESULTS. THE PATIENT SAMPLE HAS A VERY HIGH CONCENTRATION OF ANTISTREPTOLYSIN O (ASLO) WHICH IS CONFIRMED BY THE INITIAL AND REPEAT RESULTS ACCOMPANIED BY INVALIDATING DATA FLAGS AND THE RESULT FROM THE EXTERNAL LABORATORY. DURING A REVIEW OF THE ALARM TRACE DATA, "ABNORMAL ASPIRATION" AND "SAMPLE SHORTAGE" ALARMS OCCURRED ON THE DAY OF THE EVENT. THESE ALARMS SUGGEST POTENTIAL INSTRUMENT ISSUES. THE REACTION KINETICS DATA SHOWED AN UNEXPECTED TREND; THE KINETICS DATA TRENDED TO INFINITY AT THE END OF THE TIME COURSE WHEN SATURATION WOULD BE EXPECTED. IT IS NOT CLEAR WHY VERY HIGH RESULTS WERE OBTAINED FOR SOME DILUTED RUNS WHILE A LOW RESULT WAS ALSO OBTAINED ON A DILUTED RUN. THE UNEXPECTED TREND OBSERVED IN THE REACTION KINETICS DATA ALONG WITH THE DIFFERENT RESULTS OBTAINED WITH DILUTION SUGGEST AN INTERFERENCE/SAMPLE-SPECIFIC ISSUE DUE TO THE PATIENT'S CONDITION. PRODUCT LABELING STATES: "IN VERY RARE CASES, GAMMOPATHY, IN PARTICULAR TYPE IGM (WALDENSTRÖM¿S MACROGLOBULINEMIA), MAY CAUSE UNRELIABLE RESULTS. FOR DIAGNOSTIC PURPOSES, THE RESULTS SHOULD ALWAYS BE ASSESSED IN CONJUNCTION WITH THE PATIENT¿S MEDICAL HISTORY, CLINICAL EXAMINATION AND OTHER FINDINGS." THE INVESTIGATION DID NOT IDENTIFY A PRODUCT PROBLEM. THE CAUSE OF THE EVENT COULD NOT BE DETERMINED.