This method utilizes both treatment of DNA with sodium bisulfite initially, and melting curve analysis by using a thermal cycler, like the LightCycler from Roche Diagnostics, which uses a DNA-binding dye that binds double-stranded DNA, coupled to a fluorometer. A difference in the melting temperature of converted methyl-cytosines to uracil, allows one to semi-quantitate the reaction and results, as there will be subsequent differences in the GC content post-sodium bisulfite treatment.
J.Worm et al. In-tube DNA methylation profiling by fluorescence melting curve analysis. Clin Chem (2001) 47: 1183-1189.