CVS offers at-home drug tests that you can purchase and take at home so you can test yourself. A test that uses a sample of your hair can detect drugs within your system for as many as 90 days beforehand. Standard urine tests typically only provide results for the presence of drugs that have been in your system for the past three to five days. Urine drug tests can provide fast results that are typically produced within just a few minutes, and they can be done in the privacy of your own home. Aside from purchasing at-home drug tests, you may be able to get one at a CVS MinuteClinic location near you.