Drug Testing Methods

Table of Contents

Many people receive employment offers that are pending the successful outcome of a drug test. Testing for drugs can be done via urine, hair, blood or oral fluid. Each substance stays in a component of the body for different lengths of time.

Take a look at the following five examples:

  • Alcohol is usually present 6-24 hours in urine, up to 2 days in hair and 12-24 hours in blood or oral fluid
  • Cocaine is present 2-5 days in urine, up to 90 days in hair and 2 to 5 days in blood or oral fluids
  • Heroin is present 1-4 days in urine, up to 90 days in hair and 1-2 days in blood or oral fluids
  • For heavy cannabis users, the substance can stay in the urine for 10 days, up to 90 days in hair and up to two weeks in the blood
  • Ecstasy stays 20-24 hours in the urine, up to 90 days in hair and 20-24 hours in the blood

Each of the drug tests is done differently.


With a urine sample, the patient goes to a collection site or does it at home. Once received by the testing lab, the sample becomes part of a chain of custody to make sure it is not tampered with. The first testing step is to divide the urine into two parts. One is screened using an analyzer (immunoassay). If the results are positive another part of the sample is tested to confirm it.

If the test is related to employment, the results are relayed to a Medical Review Office (MRO). If the test is negative the MRO tells the employer that there is no detectable drug in the urine.


Hair testing is legally and scientifically recognized as admissible evidence in courts. Most hair tests screen for the main drugs of abuse which are cocaine, amphetamines, methamphetamines, PCP and marijuana. The guidelines for hair testing have been published by the Society of Hair Testing. These tests are popular because they are less invasive than a urine drug test and it is difficult to alter a specimen. Hair can also be tested from anywhere on the body.


Blood tests are a snapshot of whether a drug is in the body at a particular time. They are considered the most accurate way of telling if an individual is intoxicated. Blood tests are not used for drugs that often because specialized equipment and medically trained technicians are necessary for interpretation which makes the test more costly.


Oral fluid based drug tests can usually detect use within the previous few hours and up to two days. However, THC may only be detectable for less than 12 hours in most cases.

If you have a drug problem do not wait to contact Recovery First. You don’t want to lose more of your precious life to substance abuse, so the sooner you get help the better. Call an empathetic Recovery First counselor right away for immediate treatment.

About The Contributor

Editorial Staff
Editorial Staff

Editorial Staff, American Addiction Centers

The editorial staff of Recovery First is comprised of addiction content experts from American Addiction Centers. Our editors and medical reviewers have over a decade of cumulative experience in medical content editing and have reviewed thousands... Read More

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