The precipitate is due to Cu(OH)2 formation as mentioned
previously [9]. The precipitate appears when dNTP
was not consumed; it is easy to judge the precipitate with the
naked eye as mentioned [9]. The dNTP dose of LAMP
exceeds several times than PCR’s (13,14]. When the reaction
is negative, dNTP dose has not changed after the reaction, so
the precipitate appears in the negative tube when adding
CuSO4. While in the positive reaction, the dNTP density
reduced greatly so the authors could not see a precipitate in
the positive tube.