Some key things to know before reading: Height, weight, diet, exercise, genetics - all of these play a role in the rate at which drugs are metabolized through the body. If Person A and Person B stop smoking marijuana at the same time and take a drug test one month later, it is possible that Person A tests positive and Person B tests negative. The answers to these questions are as close to fact as possible, taking into account differences in metabolism.
Screening test: Only shows positive or negative for the presence of drugs. No quantities are provided.
Confirmatory test: Determines specifically how much of a drug is in the body. Typically performed after a screening, especially in a clinical setting, and clears up false positives in by showing presence of drug is insignificant.
Now let's get to it!