Ultimate Star Wars states that Asajj was a "dark assassin/acolyte" who only strives to be a true Sith.
I Am Sith lists Asajj as a "dark side warrior", who was not a true Sith.
Galactic Maps states she was just a dark side "assassin".
AEYNTK states she was just an "assassin", and not trained in the way of the Sith.
...Aside from her databank entry.