FIG. 6.

Detection of endogenous RT-PCR inhibitors in samples used for diagnosis analyzed by 5′ exonuclease (TaqMan) RT-PCR. Two dual-labeled probes, one for detection of the WNV RNA amplification product and one for detection of the heterologous competitor RNA amplification product, were included in each reaction mixture. Amplification was performed with reaction mixtures to which 20 copies of competitor RNA were added to each mixture. The horizontal line at 0.01 fluorescence units indicates the threshold for a positive reaction. dRn, baseline-corrected normalized fluorescence.