Drug Testing HR pre-employment drug screening

Hair testing: An effective option for drug testing

In September, the Department of Health and Human Services began seeking public commentary on the use of hair testing for federal employees and safety-sensitive employees. Hair testing has been around for quite some time, and employers have been using it because of its efficacy and the difficulty of cheating the test, especially when compared to urine testing. As we look forward to a more universal application of hair testing, let’s evaluate the top questions employees and employers have about drug testing.

How much hair is needed for a drug test?

For a hair test, the amount is actually determined by weight. 40 mg of hair (or approximately 50 to 70 strands at a length of 1.5 inches) is needed to determine a positive or negative hair test. For those taking the test, hair from the head is ideal, but hair from other body areas can be used as well. (As a side note, we have seen applicants remove all body hair to avoid a hair test because of the efficacy of this test.)

It is essential that a quality drug testing provider perform the test. In the past few years, we have seen many private schools and businesses release horrible pictures of drug tests gone badly, drug testing companies that removed large swathes of hair from students and employees.

A small amount of hair is required, and a quality drug testing partner can do so inconspicuously.

Is a hair test more effective than a body fluid test?

The short answer is yes. A hair test is more effective because of the length of the drug use indicated and the difficulty of cheating the test.

Detection is up to 90 days

Detection can go back 90 days or more depending on the length of the hair and process the hair has been subjected to. Why is this? Drug metabolites are stored in the hair follicle. If the applicant used drugs while the hair was growing, the hair will test positive for that drug at any point. This is the reason why it is essential that the hairs be taken as close to the body as possible—to test not only the history of drug use but also the recent drug use.


Hair tests are difficult to alter

Hair drug testing makes it difficult for specimens to be altered. The hair is taken directly from the head: there’s no observation, no time out of observation, and no opportunity for an inauthentic sample to be provided. Using this testing approach also makes it easy to obtain, store, and ship specimens.

Can secondhand smoke cause you to fail a hair follicle drug test?

This is one of the contentious points of more widely applying hair drug testing. However, even marijuana friendly websites, such as potguide.com point out that it is unlikely that secondhand smoke can cause a positive drug test for hair testing.

Are you ready to begin drug testing? WSS is an expert in all types of drug testing, and we can advise you as to which drug test is best for your business.

Discover better on-site drug and alcohol testing, 24/7 ~ SCHEDULE A TEST
left right
Recent Articles
Taking A Hard Look at Worksite Eye Injuries
Eye injuries remain one of the most common workplace injuries, despite numerous products available to protect against eye damage. For the business...
Read More
The Workplace Dangers of Rising Methamphetamine Use
One of the many unfortunate side effects of the Covid-19 pandemic is increased numbers in drug use, at a time when substance abuse was already on the...
Drug Testing
Read More
PART 2 - Employment & Background Checks: What Do They Want To Know?
Why Is My Employer Asking For A Background Check?  Last week, we discussed the basic info about employee background checks--- what they are, the wait...
Drug Testing
Read More