COBAS AMPLICOR CHLAMYDIA TACHOMATIS TEST

Description of Event or Problem

HOLD - SDA

Additional Manufacturer Narrative

DEVICE EVALUATED BY MANUFACTURER: YES. RESULT: DEVICE PERFORMED ACCORDING TO SPECIFICATIONS. CONCLUSION: FAILURE DETECTED AND PRODUCT WITHIN SPECIFICATION. URINE SAMPLES FROM TWO PATIENTS PREVIOUSLY GENERATED POSITIVE CT RESULTS. UPON RETESTING FOR A COMPARISON STUDY, NEGATIVE RESULTS WERE OBTAINED FOR SOME REPLICATES. THE SAMPLES HAD BEEN STORED AT 2-8C FOR ONE DAY AND THEN WERE FROZEN AT -20C. THE CUSTOMER REPORTED THAT THE PATIENTS WHOSE SAMPLES PRODUCED THE DISCREPANT RESULTS WERE NOT ADVERSELY AFFECTED. THE CUSTOMER WAS NOT WILLING TO PROVIDE ANY FURTHER INFORMATION FOR THE INVESTIGATION, INCLUDING KIT LOT NUMBERS OR LABORATORY STATISTICS (E.G. FALSE POSITIVE RATE, FALSE NEGATIVE RATE, PREVALENCE OF CT INFECTION, ETC). NO PATIENT SAMPLES WERE PROVIDED FOR INVESTIGATIVE TESTING. BASED ON THE LIMITED AVAILABLE INFORMATION, NO PRODUCT NON-CONFORMANCE WAS IDENTIFIED. THE ISSUE OF DISCREPANT CT RESULTS WITH THE COBAS AMPLICOR CT/NG TEST IS PLAUSIBLE AND MAY BE WITHIN THE PRODUCT LABELING CLAIMS, DEPENDING ON THE LABORATORY'S POSITIVE PREDICTIVE VALUE (PPV), NEGATIVE PREDICTIVE VALUE (NPV), FALSE POSITIVE RATE, FALSE NEGATIVE RATE, AND NUMBER OF SAMPLES TESTED. LABELING PROVIDES A NUMBER OF POSSIBLE SOURCES OF DISCREPANT RESULTS, SUCH AS PATIENT FACTORS, STATE OF INFECTION, AND PREVALENCE OF INFECTION. PRODUCT LABELING STATES SENSITIVITY FOR FEMALE URINE SPECIMENS WAS, ON AVERAGE, 90.6% AND FOR MALE SPECIMENS 89.1%. IT IS ALSO NOTED THAT THE SENSITIVITY WAS LOWER FOR FROZEN MALE URINE SPECIMENS AND HIGHER FOR FROZEN FEMALE URINE SPECIMENS, AS COMPARED TO SPECIMENS WHICH HAD NOT BEEN FROZEN. IT IS UNKNOWN WHETHER THE TWO SAMPLES WHICH GENERATED DISCREPANT RESULTS WERE MALE OR FEMALE. THE CUSTOMER DID NOT PROVIDE ANY STATISTICS THAT COULD BE USED TO DETERMINE IF THE DISCREPANT RESULTS GENERATED WERE WITHIN PRODUCT LABELING CLAIMS. (B)(4).

Additional Manufacturer Narrative

A DEFINITIVE CONCLUSION CANNOT BE DRAWN AT THIS TIME, AS THE INVESTIGATION INTO THIS ISSUE IS ONGOING. THE OUTCOME OF THE INVESTIGATION WILL BE COMMUNICATED THROUGH A FOLLOW-UP REPORT. (B)(4).

Description of Event or Problem

A CUSTOMER SITE IN (B)(6) ALLEGED THAT FALSE (B)(6) RESULTS WERE GENERATED DURING A COMPARISON STUDY WITH THE COBAS AMPLICOR CHLAMYDIA TRACHOMATIS TEST. (B)(4) THEY RAN PREVIOUSLY RUN (B)(6) SAMPLES ON THREE OF THEIR INSTRUMENTS AND GENERATED DISCREPANT RESULTS. THE SAMPLES HAD BEEN STORED AT 2-8 DEGREES FOR ONE DAY THEN WERE FROZEN AT -20 DEGREES.