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Blood Drug Testing — The Most Accurate Type of Drug Screening

Blood Drug Test

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A blood drug test is the technical analysis of blood sample, usually extracted from a vein on the inside of the arm or the back of one’s palm with a needle, or through fingerstick, to detect the use of illicit drugs. Unlike urine test (aka urinalysis), blood test detects the presence of the parent drug and not its inactive metabolites. Metabolites are the products created when the body breaks down the drug through the process of metabolism.

Table of Contents

Drugs Detectable in Blood Test and Detection Windows

Which drugs can be detected in blood?

The drugs that can be detected in the blood are:

  • Amphetamines
  • Methamphetamine
  • Barbiturates
  • Benzodiazepines
  • Cannabis
  • Cocaine
  • Codeine
  • Cotinine
  • LSD
  • PCP

A blood test has very short detection window for almost all drugs, especially marijuana (Cannabis). It normally disappears from the bloodstream within six hours, but for heavy smokers may be detectable for up to 24 hours. This means that after-hours smokers don’t really have to worry about being tested positive.

The following drug detection window data is an approximate evaluation and may vary for different individuals. The only foolproof way to pass a drug test is to stay clean and avoid any drug use.
  • Amphetamines: 10-14 hours
  • Methamphetamine: 24 hours
  • Barbiturates: 1-2 days
  • Benzodiazepines: 6 — 48 hours
  • Cannabis: 6-24 hours
  • Cocaine: 12-24 hours
  • Codeine: 6-12 hours
  • Cotinine (metabolite of nicotine): 12-48 hours
  • LSD: 0 — 3 hours
  • PCP: 12-24 hours
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Are blood drug tests accurate?

Yes, blood drug tests are accurate and virtually impossible to beat. Legally prescribed drugs can also be detected using this test. However, blood tests are not commonly used due to their invasiveness, cost, required equipment, and long waiting time to get results.

Blood Drug Test — Accurate, But not Common

If administered during the detection window, blood testing is the most accurate approach for detecting drugs. Moreover, it’s the type of test that’s virtually impossible to beat, and if the donor takes any adulterants – no matter even if they are legal – they also might be detected in the blood.
However, it is not very common because of several reasons. Firstly, it’s the most invasive of all the drug tests. Secondly, it is one of the most, if not the most expensive blood test. What’s more, it requires medically trained administrators and specialized equipment, and yet the results can take up to a week, while several other tests such as saliva test or urinalysis can offer on the spot results.

When is a Blood Test Required?

Blood drug testing is required for people who are applying for insurance, for potential employees applying for jobs, and in some cases blood tests are required as part of a court order.
As mentioned earlier, a blood test is not very common and is only required when significant amounts of money, or the law, are involved. There are however certain cases where a blood drug test might be required. Insurance companies can require a blood drug test when a person applies for an insurance policy. An employer may require their potential employees for drug screen through a blood test before hiring. In rare cases, a blood test may also be required by court order.

Passing a Blood Test

Since blood test has a short detection window, it’s generally easy to pass it. Simply not taking drugs will give one the best chance to pass a blood sample drug test. Since adulterants which some individuals take to beat drug tests are very easy to detect, using them can be counterproductive. Eating healthy foods, drinking plenty of water, and fresh juices, and doing exercise can help the body quickly detoxify the drugs which are present.

AddictionResource does not encourage the use of any substances for non-medical purposes and does not provide the information on how to cheat on the drug tests. The attempts to falsificate the drug test results may be subject to legal prosecution.
  1. Hadland S. E., Levy S. Objective Testing: Urine and Other Drug Tests. Child Adolesc Psychiatric Clinics of North America. 2016; 25(3): 549–565. doi:10.1016/j.chc.2016.02.005.
  2. McNeil S. E., Cogburn M. 2019. Treasure Island (FL): StatPearls Publishing.
  3. DETECTION AND MEASUREMENT OF DRUGS. National Highway Traffic Safety Administration.