Jeremiah, I don't think Mixolydian is a definition of a blues scale - it has a major 3rd, and if it carries any descriptive name I'd think it would probably be something like the Celtic scale, because that dropped 7th is a distinctive feature of much of the music. Blues traditionally has a minor 3rd, and the two common minor scales are the Dorian and the Aeolian, the difference between them being a raised 6th (Dorian) or lowered 6th (Aeolian). The Phrygian has a minor 3rd in it, but always sounds - to my ear at least - like an Ionian that someone forgot to finish, rather than a true minor scale.

The "blues scale" that I know of - just to keep life from being too simple - is not one of these seven. It has gaps in it and a flat 5th as well as the natural 5th. In other words, if you played it on a piano keyboard (or any other instrument, come to that) starting on C, it would be (trying to type this while listening to Fidelio in the headphones!):

C D Eb F Gb G Bb C

Or you can leave the D out: I sometimes tune my harp this way and play scales (or make the D into D# so it rings against the Eb) which takes some of the tedium out of them.