Visual sensitivity of LAMP reactions using SYBR Green I. (a) Direct detection by the naked eye, (b) under UV transillumination. Tubes 1–7, 2 × 105, 2 × 104, 2 × 103, 2 × 102, 2 × 101, 2 × 100, 2 × 10−1 copies per tube, respectively; tube 8, negative control without DNA.