Understanding Drug Testing
Drug tests detect the presence of substances or their metabolites — the breakdown products your body creates as it processes a drug. Different testing methods have different detection windows because they measure different things: blood tests detect the active drug, urine tests detect metabolites excreted by the kidneys, hair tests detect substances incorporated into the growing hair shaft, and saliva tests detect drugs present in oral fluid.
The detection times listed in this guide represent typical ranges for standard immunoassay screening tests. Individual results vary based on factors discussed at the end of this article. These times assume standard cutoff levels used by most workplace and clinical testing programs.
Detection Time Table
* Cannabis detection in urine is highly variable — see section below. ** Benzodiazepine detection depends heavily on which specific benzo — see section below. *** Urine EtG (ethyl glucuronide) test can detect alcohol metabolites up to 80 hours.