Yes, if you are using TwistAmp® Basic, nfo or fpg reactions. However the reaction components are activated as soon as magnesium is added. By pipetting magnesium acetate into the reaction last, which we recommend, for example by adding it to the lids of strips and spinning it into the reactions, you ensure that reactions start simultaneously and you minimise the risk of cross contamination or RPA products being produced in any reaction residues left in your tips.
No, if you are using TwistAmp® exo or TwistAmp® exo RT reactions. In the presence of Mg, the exonuclease can attack the primers and probes before they are protected by the recombinase and singlestranded binding proteins. This may cause a high fluorescence base line in your reactions.