Optimizing the duration of the RT-LAMP reaction. RT-LAMP was used to amplify PRRSV containing samples. The products of the RT-LAMP reactions were visualized by (A) 1% agarose gel electrophoresis, (B) UV transillumination, and (C) color change using SYBR Green I dye. Lanes M; DL2000 Marker (A only), 1-5; 45, 50. 55, 60, and 65 min, respectively.