Quote Originally Posted by dfguy
So back to the Half-live, Lets say you were at 100 ng/mL on Aug. 1, and the half-life for you is 10 days, on Aug. 10th. you would be at 50 ng/mL, might fail a drug "screen", on Aug 20th, you would be at 25 ng/mL , you would pass a "screen" , but fail a "test" (GC/MS). On Aug. 30th. you would be at 12.5 ng/mL, 10 days later 6.25 ng/mL, 10 more 3.12, and so on and so on. Yours might be less, or Like me, longer.
Exactly Dfguy, great example. The technical definition would be the time required for half the amount of a substance (as a drug or radioactive tracer) in or introduced into a living system or ecosystem to be eliminated or disintegrated by natural processes. So for every half life completed, half of the THC will be eliminated. In Dfguy's example, that doesn't mean that on August 9 you would still be at the level you were on August 1 and suddenly on August 10 it makes this huge drop off. It is constantly eliminated but the measuring milestones are measured in half-lifes. Even though this link and graph represent radioactive half-life, the graph would be the same for THC.

http://www.lbl.gov/abc/experiments/Experiment6.html

The point 1 on the left side of the graph would represent the time when you last consumed THC and the graph would be accurate unless more THC were introduced to your system. Disregard the numbers on the bottom of the graph as these numbers would represent the half life of THC. Unfortunately, these numbers vary greatly from person to person. The increments could be as small 20 hours (then 40 hours, 60 hours, 80 hours, 100 hours etc) or as long as 10 days (then 20 days, then 30 days, then 40 days etc.).