Endpoint assessment
HNB dye was dissolved in distilled water at 20 mM to prepare a stock solution.
The LAMP assay containing 120 μMof HNB dye was performed in a 25 μl reaction mixture
with the same components as in the RT-LAMP assay except excluding the (FD) reagent. Turbidity of the RT-LAMP assay was observed with the naked eye. A positive reaction was indicated by a color change from violet to sky blue. On top of that, PCR was performed on 4 μL LAMP products using F3 and B3 primers with the same reaction mixture as above with the following PCR cycles: 94°C for 4 min; 35 cycles at 94°C for 30 s, annealing at 55°C for 1 min, extension at 72°C for 30 s.