A customer in the united states reported that their internal control (ms2 plasmid) values are lower than expected after changing lots of nuclisens® lysis buffer (lot z019ko1) for nucleic acid extraction.The customer was testing patient rectal samples with a downstream application, luminex gpp (gastrointestinal pathogen panel).The customer stated there was no patient impact, as they repeat testing when there is an internal control failure.If it fails twice the test is reported as invalid.The customer reported that they had to do this a few times, and there have been results that were delayed more than 24 hours.In these cases, the customer did not know if patient results or treatment was impacted.A biomérieux internal investigation will be initiated.
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An internal biomérieux investigation was performed for a customer report that their internal control (ms2 plasmid) values were lower than expected after changing lots of nuclisens® lysis buffer for nucleic acid extraction.The customer was testing patient rectal samples with a downstream application, luminex gpp (gastrointestinal pathogen panel).The batch history record review as well as the complaint history performed for the lysis buffer (ref 280134, lot z019ko1lb) highlighted no issue.Investigation summary: analytical tests: the ph and triton content of the impacted batch were in conformance.Functional tests: several functional experiments were performed in conditions as close as possible to those used by the customer.Biomérieux tested the same extraction reagents (buffers and silica) as the customer on different viral targets (enterovirus, adenovirus and hsv2) representative of those of the luminex gpp panel used by the customer.The tests were performed on stool samples, as the customer tests, and also on utm (universal transport medium) or plasma samples, in order to highlight the effects of the potential heavy content of inhibitors in stool samples.All the tests have been performed with biomérieux's pcr & rt pcr molecular assays.These experiments showed that the lysis buffer ref 280134 lot z019ko1lb allows perfectly to lyse, extract and purify the nucleic acid of the targets.No impact on the results have been observed.Conclusion: the customer's results were not reproduced in-house.With internal assays, the lysis buffer is within conformance.The investigation did not identify a root cause.The issue seems to be linked to residual inhibitors still present in the stool samples after extraction.
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