Investigation of this complaint found that the instrument operated within specification during execution of the "7hour" protocol, which started in retort a at 21:02 pm on (b)(4) 2016 and completed successfully at 07:45am on (b)(4) 2016, from which sub-optimal tissue processing was reported by the complainant.The root cause of the sub-optimal tissue processing reported was the combined use of ethanol from bottle 9 at a concentration of 80.2% for the fifth of the six dehydration steps in the "7hour" protocol started in retort a at 21:02 pm on (b)(4) 2016; and ethanol from bottle 7 at a concentration of 70% for the final dehydration step in the "7hour" protocol started in retort a at 21:02 pm on (b)(4) 2016.The minimum final reagent concentration required for ethanol is 98%.The consequences of using ethanol at a concentration less than the minimum required for the final dehydration step in a protocol is re-introduction of water into the tissue which cannot be displaced in subsequent processing steps; and contamination of reagents used in the subsequent processing steps, ultimately resulting in sub-optimal tissue processing.Although bottles 7 and 9 are designated as , bottles 7 and 9 were filled with 70% and 80% ethanol respectively on (b)(4) 2016 as detailed in mfr.Report# 8020030-2016-00041, which has been submitted previously.The root cause for bottles 9 and 7 being used for the penultimate and final dehydration steps of the "7hour" protocol started in retort a at 21:02 pm on (b)(4) 2016 was a combination of the reagent management being set as .Reagents initially scheduled for use in the "7hour" protocol started in retort a at 21:02 pm on (b)(4) 2016 had already been scheduled for a protocol which started in retort b prior to commencement of the protocol in retort a.As a consequence of the lack of availability of the reagent in bottles 5 and 4 initially scheduled for use in the "7hour" protocol started in retort a at 21:02 pm on (b)(4) 2016, the instrument functioned as designed by allocating an alternative reagent with the lowest number of cycles for both the penultimate and final dehydration steps of the "7hour" protocol started in retort a at 21:02 pm on (b)(4) 2016, which was bottle 9 and 7 respectively.
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