A customer from the us alleged generation of false positive results for target 2 (sarbecovirus) with the cobas 6800/8800 sars-cov-2 test.Four false positive results, with early ct values, occurred due to suspected issues with the front process head in a specific well position of the cobas 8800 system.Sample 1: generated positive result for target 2 on 2.2.21 at 12:50 hours ct value (8.32) the sample was retested which generated negative result for target 2 on 2.2.21 at 3:39 hours.Sample2: generated positive result for target 2 on 2.3.21 at 4:41 hours ct value (7.73) the sample was retested which generated negative result for target 2 on 2.04.21 at 1:58 hours.Sample 3: generated positive result for target 2 ct value (8,01) the sample was retested which generated negative result for target 2.Sample 4: generated positive result for target 2 ct value (8.16) the sample was retested which generated negative result for target 2.The negative results were reported out and no harm or injury is alleged.4 mdrs, one per each alleged result, will be filed.
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Data analysis showed that samples having early target ct values (6 to 8), at the same time a low rfi value (1.6 to 1.8) and declared as positive only for target 2: pan-sarbecovirus were found to be located in ad position h11 and preparation position h6.Data used for this investigation showed that in the timeframe between november 2020 and february 2021 a total of 27¿000 samples were processed with instrument cobas 8800 sn (b)(4).A total of 14 samples were identified with rare outlier results with early target ct values and low rfi values.This gives an approximate occurrence rate of (b)(4).It is also important to note that this was the only cobas 8800 system at this customer site demonstrating this issue.Troubleshooting efforts and service actions took place at the customer site, which involved the replacement of several instrument parts, including he head processing transfer front, stop disc slotted set of 48, sealing station, separation station front, amplification plate park position and heating station front.These replacements did not have any influence on the occurrence of early target ct values with low rfi values.After the exchange of additional, instrument parts (pump microgear assy, needle reagent transfer assy, and tube fep d3.2/1.6 assy l240), no more samples with early target ct values and low rfi values were observed during customer testing.None of these parts were returned for further investigation.Analyses of instrument checks (pipetting check, needle bent check, tightness check, and ultrasonic data) showed that the pump microgear assy, needle reagent transfer assy, and tube fep d3.2/1.6 assy l240 were working within specifications.A processed sample from the customer site that exhibited an early ct value and low rfi value (in position h11) was subject to additional in-house analysis.The sequence indicated that the amplified sample was not a true positive sample.The customer issue has been alleged on the cobas 8800 system, product code: mza, catalog number 05412722001 and udi (b)(4).The test used on the cobas 6800/8800 system is the cobas sars-cov-2 test for use on the cobas 6800/8800 system, product code qjr, catalog number 09343733190 and udi (b)(4).Update the suspect medical device to the cobas sars-cov-2 test for use on the cobas 6800/8800 system per fda request on 17-jun-2021 ((b)(4)).Corrected section g to update the manufacturing site details for the cobas sars-cov-2 test for use on the cobas 6800/8800 system per fda request on 17-jun-2021 ((b)(4)).(b)(4).
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