Hair drug test in 3 wks and i have taken a total of 125 mg of vyvanse (lisdexamfetamine) in the past 3 months. the last dose was 25mg a week ago. will i test positive?

Hair drug tests : generally detect drugs that have been used 3 or > times within 90 days prior to testing, including use that occurred 7-10 days prior to testing. Hair testing picks up low-dose amphetamine (AMPH) use; Quest Lab's cut-off for a + screen is 300 pg/mg (picograms/milligram); other labs use 500 pg/mg.It's possible that your AMPH will " show up" at a level under the cut-off point.