TINA-QUANT CYSTATIN C GEN.2

Additional Manufacturer Narrative

THE COBAS 8000 COBAS C 502 MODULE SERIAL NUMBER IS (B)(6). THE INVESTIGATION IS ONGOING.

Description of Event or Problem

THE INITIAL REPORTER RECEIVED QUESTIONABLE TINA-QUANT CYSTATIN C GEN.2 RESULTS FROM SIX SAMPLES FROM THE SAME PATIENT TESTED ON THE COBAS 8000 COBAS C 502 MODULE. THE REPORTER STATED THAT THE PATIENT'S RESULTS HAD BEEN STEADY AT 1.3 MG/L IN EARLY (B)(6) 2025. AROUND LATE (B)(6) 2025, THE PATIENT WAS ADMINISTERED A RABBIT-RELATED DRUG. THEY SUSPECT THAT THE PATIENT PRODUCED RABBIT ANTIBODIES IN MID- (B)(6) 2025 AFTER THE DRUG ADMINISTRATION, WHICH INTERFERED WITH THE ASSAY. PLEASE REFER TO THE ATTACHMENT (B)(6) IN THE MEDWATCH FOR THE TABLE CONTAINING THE DISCREPANT RESULTS OF THE SIX PATIENT SAMPLES.

Additional Manufacturer Narrative

THE INVESTIGATION INCLUDED A REVIEW OF THE DATA SET PROVIDED BY THE CUSTOMER: SEVERAL CALIBRATIONS HAD FLAGS. THE QCS HAD OUT-OF-RANGE RESULTS. THE REACTION MONITORS SHOWED AN INCREASED ABSORBANCE. THE INVESTIGATION NOTED THAT THE CUSTOMER USED QC AS A DILUENT. PRODUCT LABELING STATES, "MATERIALS REQUIRED (BUT NOT PROVIDED) NACL DILUENT 9 %... FOR AUTOMATIC POSTDILUTION AND STANDARD SERIAL DILUTION." THE INVESTIGATION NOTED THAT THE PATIENT WAS ADMINISTERED A RABBIT-RELATED DRUG. PRODUCT LABELING STATES, "IN VERY RARE CASES, FALSELY ELEVATED RESULTS FOR CYSTATIN C WILL BE OBTAINED FROM SAMPLES TAKEN FROM PATIENTS WHO HAVE BEEN TREATED WITH RABBIT ANTIBODIES OR HAVE DEVELOPED ANTI-RABBIT ANTIBODIES. FOR DIAGNOSTIC PURPOSES, THE RESULTS SHOULD ALWAYS BE ASSESSED IN CONJUNCTION WITH THE PATIENT¿S MEDICAL HISTORY, CLINICAL EXAMINATION AND OTHER FINDINGS." THE INVESTIGATION DETERMINED THAT THE EVENT WAS CONSISTENT WITH THE EFFECT OF THE RABBIT ANTIBODIES PRODUCED BY THE PATIENT AFTER DRUG ADMINISTRATION. THE INVESTIGATION DID NOT IDENTIFY A PRODUCT PROBLEM.