Reproducibility. The interassay coefficient of variation (based
on the calculated HA RNA concentration expressed in number
of copies per ml of water) was calculated from the results of
eight consecutive qRT-PCR assays performed over a 2-weekperiod, using ddw samples artificially inoculated with H5N1
virus and stored at 4°C. The samples were extracted either
directly or after treatment with CRBCs. Similarly, the intraassay
coefficient of variation was calculated from the results of
six qRT-PCR assays. The experimental intra- and interassay
variability values obtained using different virus loads are summarized
in Table 3.