Simultaneous detection of viral RNA and contaminating DNA. Serial ten-fold dilutions of viral RNA with approximately 1,000 copies of heterologous competitor (amplicon) DNA per reaction were amplified following incubation for 20 min at 30°C either without (A) or with (B) 0.25 U UNG per reaction. Reactions were performed in triplicate and contained approximately 250,000 copies viral RNA (●), 25,000 copies viral RNA (▼), 2,500 copies viral RNA (■) or 250 copies viral RNA (◆). Each reaction contained 1,000 copies of amplicon DNA. The fluorescence signal generated by amplicon DNA is indicated by the open form of the same symbol for each respective reaction. The horizontal line at approximately 0.008 fluorescence units (dRn) indicates the threshold for a positive reaction. dRn, baseline-corrected normalized fluorescence.