However, the TL/CL value derived from this mixture was significantly different at 320 HAU/mL (P <0.01) and 1,280 HAU/mL (P <0.001) for detecting influenza A at F650 implying that the F650 could not eliminate the leaky fluorescent signal derived from the mixture and that the viral concentration of 320-1,280 HAU/mL may also have influenced the cross signaling of QD580 at F650 (Fig.  7A) .