Eli5 How far back do drug tests check?


I don’t know how to phrase the title, I’m sorry.
ANYWAYS, do drug tests check if you’ve EVER done drugs, or or in a specific amount of time? Or does it depend on anything else?

In: 8

Urine and blood tests can only check what is currently in your system. Some drugs can go through your system really fast, like alcohol (most drug tests don’t check for this anyway). Some can stay in your system for a month or more, like marijuana.

Hair tests, which are very uncommon, can detect drug usage from much further back since the traces of drugs basically get stuck in your hair as it grows out.

Drug tests detect the presence of certain drugs in a person’s system, usually in the form of urine, saliva, or hair samples. The amount of time that a drug test can detect drugs depends on the type of drug and the type of test used. Generally, urine drug tests can detect drugs for up to 3 days after last use, while saliva tests can detect drugs for up to 24-48 hours after last use. Hair tests can detect drugs for up to 90 days after last use.

Pot – Up to a month and a half, but an average of a couple weeks.
Coke/meth/X – one week
Depends on the length, but typically 3-6 months

Depends on the drug and the testing method.

The presence of drugs *themselves* will only show up while they’re in your system, but most drug tests check for metabolites (byproducts of drug metabolization,) which can hang around for much longer, especially if your body stores them in fat cells. Of course, it’s also possible to test hair follicles, which can hold metabolites for some drugs for several months.