Hi,

I  usually work with M13-tagged PCR primers. I use this tail because I need an amplicon with MID to identify every patient included in 454-sequencing (as Bybee et al, Genome Biol Evol, 2011). 

It has been working with high viral load in serum (>105 IU/mL)but not with lower viral load. Is it possible that primer-dimer of M13-tail can be formed easier when viral load is low? Have you got any problems with M13-tails?

Maybe .. is it possible to increase annealing temperature to make easier DNA-primer instead of primer-primer?

Thank you so much!