If a drug test is positive, can it be determined how long ago the drug was taken and over what period of time?
Drug of abuse testing by blood, urine, or saliva can only detect whether or not a specific drug or drug metabolite is present at the time the test is performed.
Many factors unique to the individual being tested determine the actual half-life of a drug. Some of these factors are:
- metabolic rate
- overall health
- The amount of drug consumed over what period of time, etc.
Therefore, no conclusions can be drawn as to when a drug was taken or how much was consumed with these types of drug tests.