Blues scale: is this accurate?

Doesn't matter what instrument you use, or what key you're in, a blues
scale consists of

the root (first note of the scale)
lowered (minor) 3rd (no 2nd scale step)
the 4th
lowered 5th
natural 5th
lowered 7th (no 6th step)
root (octave higher)

So, for example, a blues scale in C would be:

C E flat F Gflat G natural B flat C

A blues scale has seven notes and includes a flatted 3rd, 5th and 7th.
These three flatted notes are often referred to as "blue notes."

See:

Essentials of Music Theory: Complete Self-Study Course
http://www.sheetmusicplus.com/a/item.html?id=186635&item=5817807