In collaboration with cdc and four ar lab network public health laboratories, we evaluated the thermofisher sensititre gn7f panel.We followed the sensititre 037-nfast fda-usa only instructions for use -cid: 10253.Based on previous issues with a ruo sensititre panel (gnx2f), we evaluated whether the gn7f panel had similar performance issues.The five labs in this study followed the same protocol to evaluate the different transfer inoculum volumes (standard [10ul from 0.5 mcfarland equivalent to 11ml camhb] and increased [30ul from 0.5 mcfarland equivalent to 11ml camhb]) (see pg 4 in ifu).In addition, we evaluated the performance of the specific inoculum instructions for the proteeae tribe organisms (1ul from 0.5 mcfarland equivalent to 11ml camhb).These various inoculum levels were tested from the same 0.5 mcfarland equivalent to be able to compare the effect of these inoculum methods.Methods were otherwise according to the ifu, with the exception of two labs who used a turbidity meter instead of a sensititre nephelometer.All labs manually read the gn7f panel.In one lab, in addition to the manual read, read the panels with the aris 2x.All labs tested the same 100 organisms from the cdc & fda ar isolate bank (40 enterobacterales, 30 p.Aeruginosa, and 30 a.Baumannii).The greatest effect of the 1ul/10ul standard inoculum methods was observed for enterobacterales.All laboratories saw that using the 1ul with the proteeae tribe undercalled resistance, specifically in the beta-lactam agents.Amongst all laboratories, using the 1ul for proteeae tribe and 10ul for non-proteeae tribe, no lab could obtain essential agreement >90% for doripenem, ertapenem, imipenem, meropenem, cefepime, piperacillin-tazobactam.All labs observed at least 1 very major error (up to 5) for doripenem, ertapenem, meropenem, aztreonam, ceftolozane-tazobactam, and piperacillin-tazobactam.Increasing the transfer inoculum of all organisms to 30ul or 50ul (off-label) improved ea and very major error rates.Data can be provided upon request.The product was advertised as fda cleared.Laboratories were unable to verify product performance as advertised.Alterations in use requiring a full validation were necessary.Proteae members were diluted 1:11,000 (1 ¿l into 11 ml) per manufacturer's package insert.Using this concentration produced errors and the process had to be modified to meet standards.Validating the panel required 30 ul inoculum for all species and a manual reading of the proteeae tribe to meet validation standards.Sensititre gn7f plate lot(s): b0121a, b0227a, lot b1384 sensititre dh2o, lot(s): sensititre 11ml camhb, lot(s): 407693.Fda safety report id# (b)(4).
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