Drug Tests: How Do They Work and
Are They Accurate?

No matter where you go or what you do in life, you are likely to come across a situation that requires you to submit a drug test. Employers usually require applicants to do a drug and alcohol test before being hired. The same goes for when you are applying for health or life insurance.

Many people fear of having a test result coming up positive when it should actually be negative. And in fact there have been instances where drug tests have produced false positives or false negatives.

How Drugs Tests Work

When you are giving a blood, urine or any other sample, the focus is on your metabolites; these are the remnants of substances you may have consumed. Depending on the substance, metabolites may remain in your system for hours, or weeks.

So if you've smoked pot or done any other drug, you may not be able to pass a drug test for a while. It is hard to determine when the drugs will be out of your system - it all depends on your metabolism and the substance used.

What also stores metabolites is hair. There are some places that use strands of hair for drug testing. Hair grows quickly, so the metabolites are easily detectable soon after using a drug. The core of the hair traps the metabolites as it is growing from your skin. It is impossible to remove them by washing or bleaching. In fact, the metabolites stay within the hair's follicles for a long while. It only takes five days for the metabolites to become detectable in your hair.

How Long Do Some Drugs Stay in Your Body?

Here is an idea of how long the most popular drugs last in your system:

Alcohol - Many people don't look at beer and wine as a drug, but it is and it can definitely show up in drug tests. It can stay in your system between one to 12 hours, depending on how much was consumed.

Anabolic Steroids - This can stay in your body up to three weeks if taken by mouth and up to three to six months if injected.

Cocaine - This drug is detectable in your body between 24 to 48 hours after use.

Marijuana - Depends on how heavy a user you are. It can be between two to five days for the light user or 30+ days for the heavy smoker.

Heroine - Can stay in your system for one to two days.

Methadone - Detectable for one to seven days.

Tobacco - Drug tests detect tobacco for one to two days after use.

Opiates - Takes one to two days to leave your body.

PCP - Usually lasts between one to eight days in your system.

Different Ways of Testing for Drugs

Out of the different drug tests that are available, none of them are perfect. Each have their pros and cons, and the use of each depends on the needs of the entity running the tests.

Urine Drug Tests - This is the most common drug test out there; likely you've done a couple throughout your lifetime. These kits are usually tested and studied on-site; sometimes they are sent to a lab for results. Urine tests are sometimes referred to the "gold standard". There are some negatives for the companies that use this from of testing. Some people have succeeded in cheating on these tests by sneaking in a substitute urine sample. Also, employers aren't able to detect workers who are current drug users with urine tests because the results don't tell when the drugs were used.

Hair Drug Tests - With hair drug tests, the detection of drug and alcohol use can be detected up to 90 days or more after consumption. It is a lot harder for individuals to fake this test since the sample is taken directly from the head at testing. This way of drug testing is easier for the donor than other testing methods. This form of testing also has a high rate of accuracy. A lab is required to run the testing, so there is a longer wait for the results and it could be pricier than other drug tests. There have been some false positives for the individuals with darker hair. Some people do try to cheat this test by shaving some hair off.

Blood Drug Tests - These aren't as common as the other drug testing methods. Blood samples are usually required for serious employment positions and health insurance policies. It can be pretty expensive, which is one of the main reasons for its non-use. With a blood test, you can detect up-to-date usage of alcohol and drugs, which isn't possible with the urine and hair samples (not all cases are conclusive).

Saliva Drug Tests - The saliva test works similarly to the urine test. The only difference, of course, is the fluid used. Saliva tests aren't as accurate as urine tests, but they are very convenient, allowing employers to do random drug testing. This is also used on post-accident cases. When the saliva is used, it can detec:

  • Marijuana usage after an hour of consumption and up to one day after its use.
  • Cocaine right after use and up to two to three days after.
  • Methamphetamine/Ecstasy right after use and up to two to three days after.
  • Opiates right after use and up to two to three days after.

Cheating on Drug Tests

Many people attempt to beat drug tests by drinking lots of water or consuming products that claim to detox the system for a specific time period - usually between one to six hours. This can sometimes work, though test results do detect when profuse amounts of water is consumed, and may be rejected.

The detox products work mainly because they contain a lot of sugar.  This raises insulin, which should keep fat from being broken down.  This will reduce the concentration of fat-soluble drugs in the blood stream or urine.

Getting Your Own Blood Tested

You may want to get your own tests, just to confirm that your results before you actually apply.  If you want to do that, I’ve arranged a very good value on lab testing for you.  Check it out my page on How to Order Your Own Low-Cost Lab Tests.

How Accurate Are Drug Tests?

It's hard to believe some indications of accuracy of drug tests when most statistics are biased. Those who are for drug tests claim higher percentages of accuracy and those against drug tests show lower percentages of accuracy. The NIDA, National Institute of Drug Abuse, has labs that are generally accurate. It is government-owned and was formed to regulate the drug testing industry. Most of the drugs testing facilities abide by NIDAs standards. Safe cut-offs were created by the NIDA to prevent false positives. Different tools are used for urine testing that help to make them highly accurate - after the EMIT screening, the results are confirmed on the GC-MS. If the test comes back positive after the EMIT screening, the process moves on to the GC-MS; many companies really want the test results to come back negative during the screening to avoid additional costs of sending the samples for GC-MS confirmation. Companies that avoid using the GC-MS because of costs witness higher numbers of inaccurate drug tests.

What Are Some Causes for Drug Test Inaccuracies?

There are some foods, drinks and medications that can cause your drug test to bring up a false positive. Here are some:

Ibuprofen - Even low dosages of this pain reliever can cause false positives of THC in your system. There have been some changes to the EMIT screening to help prevent this from occurring; another enzyme is used instead. It is said that the GC-MS can make the distinction between THC and Ibuprofen.

Other medicines - There are approximately 300 cold, fever, pain and diet over-the-counter medicines that can also contribute to false positives on drug tests.

Antibiotics - Some antibiotics, such as Amoxicillin can test positive for cocaine or heroine (in some instances).

Novocain - This and other products used during dental visits can also cause false positives.

Products With Legal Dosages of Illegal Substances

There are some foods that test positive because they contain small amounts of illegal chemicals or substances with similar characteristics.

Poppy seeds are known for causing false positives for opiates. Results can show you as a high level user - just 100 poppy seeds can cause this. Poppy seeds have the same metabolites that opiates have. There are different patterns with both, which can be viewed with the GC-MS.

Supplements with testosterone can also cause false positives, like with orchic extract, Viraloid and ZMA. These can all cause the results to come back positive for steroid use.

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