were evaluated (such as CHN and UK: Fig. 1), the amplification timewas extended, and therefore these sets were considered unsuitablefor further evaluation (data not shown).To evaluate the performance of the multiplex RT-LAMP assays,300 FMDV samples were tested and the results were comparedwith a real-time RT-PCR assay. The multiplex RT-LAMP assaysdemonstrated diagnostic sensitivities of 98.0% (243/248), 97.6%(242/248), 96.0% (238/248) and 94.8% (235/248) for assay combinations CHN/82, JPN/81, JPN/12 and UK/12, respectively (Table 2).A comparison between representative data generated by real-timeRT-PCR and a multiplex LAMP assay is shown in Fig. 2. Across themultiplex panels, the samples that generated a positive real-timeRT-PCR result (with a Ct value less than 32.0) but were negativeusing the RT-LAMP comprised 13 different samples: 3 were sharedbetween JPN/81 and JPN/12 assays, 2 were shared between CHN/82and UK/12 assays and the remaining were unique to individualassays. Seventeen samples that generated duplicate Ct values in therange >32 and <50 were also assigned as positive (Table 2). Mostof these samples also produced positive results when tested by themultiplex RT-LAMP assays (Table 2). Selected samples that were real-time RT-PCR positive but failed to generate a signal using the RT-LAMP assay were tested further. For example, repeat testing of the two samples that were real-time RT-PCR positive, but negative using the best performing multiplex RT-LAMP combination (CHN and 82 primer sets) generated positive signals for 4/5 replicates of one of the samples (O/SUD/3/2005), while only 2/5 replicates were RT-LAMP positive for the other sample (O/SUD/1/99). Furthermore, the Tp values for these replicates were high (39:12, 49:36,51:00, 56:18 and 53:06, 56:18 for O/SUD/3/2005 and O/SUD/1/99,
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