I think what you are asking is it the same reference range as if you just took a urine test without dmps,well they should of gave you an unchelated urine test first then the challenge test.
Honestly if i were you i would not have that tst done again,i had one done,without any option or explanation of its purpose or risk,if you had your amalgams out it is a bit safer,but i still had mine when it was done.
Btw was it oral,or IV
Oral is more safe IV is risky.
Its expensive and not worth doing.
A hair folicle test is the most safe and accurate,but you need to find someone who is very experienced at interperiting the results.