We do a urine test. Nicotine stays in the body from 3-10 days. If individuals come in as smokers we give them two weeks to be on patches and then test them two weeks later. Almost always those who come in as smokers and want to continue smoking for two weeks, never quit smoking. That is why we only allow them to use patches and not smoke the first two weeks.
If a person truly does not want to quit smoking they should find anotehr place to live.