3 doctors weighed in:

Can a drug test tell how long ago and how much of the drug you took?

3 doctors weighed in
Dr. Steven Reidbord
Psychiatry
2 doctors agree

In brief: Not generally

Some drug tests simply give a yes or no answer. However, when a drug test quantifies the amount detected in the blood or urine, it's often possible to estimate how long ago a known dosage was taken, or, conversely, the dosage given knowledge of how long ago it was taken.
I.E., if you know one, it's sometimes possible to estimate the other.

In brief: Not generally

Some drug tests simply give a yes or no answer. However, when a drug test quantifies the amount detected in the blood or urine, it's often possible to estimate how long ago a known dosage was taken, or, conversely, the dosage given knowledge of how long ago it was taken.
I.E., if you know one, it's sometimes possible to estimate the other.
Dr. Steven Reidbord
Dr. Steven Reidbord
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