RE:RE:RE:RE:RE:WOW !!I don't think its a buyout, I suspect that someone searching for "undervalued" stocks is taking up a significant position and eating up the shares in the process. It should level off (unless good news follows).
Similar event happened this week with Kraken (PNG). In two days it went from 60 cents to $1.15 and has settled a bit (for now). Imo, it was undervalued, with decent revenue and a strong outlook.
Mdx still needs to prove itself with some big contracts/news to warrant this move.
A couple other possibilities.......someone got a mystery phone call to start buying as good news is coming........regardless, congrats to all the long time holders, Rubberband comes to mind....excellent share price movement! Bonne weekend tout le monde!