A drug screen refers to an initial assay type test. The EMIT is a drug screen. It 'screens' out all 31 cannibiloid metabolites and anything that closly resembles a THC metabolite. If it screens out a mass of more that 50ng/ml, the test is possitive for pot. All home test are assay screens. A GC/MS 'test' is generally used to confirm an initial possitive on the 'screen'. For pot, the GC/MS only detects 1 singular metabolte, THCA/THC-COOH. If it detects a mass of more the 15ng/ml of THCA, it is a confirmed possitive and will stand up in court. Hope that helps. N2
PS because of your size, I strongly recomend you reconcider substituting a clean sample. While we all have differing metabolism speeds, I know from personal expermentation the I take 6-8 days to drop to a level that can be diluted to a passing level. IN GENERAL, the heavier you are, the longer that time frame is. I am 47, 5'6", 158lbs and a couch potato.