FAQ: What Employers Should Know About Drug Testing Types


When reviewing or starting a new drug-testing program in your organization, you will likely have many questions. Designing an effective program requires an understanding of the different types of drug tests, as well as how they are useful in the workplace environment. We’ll answer some of the most frequently asked questions about drug test types to help inform your decisions when designing or improving your program.

Can hair follicle testing be used for all drug-testing scenarios?

Employers often wonder whether it is necessary to use multiple types of drug tests, or if one type of test can be used for all their drug-testing needs. When it comes to the question of using just one kind of test, the hair follicle test is the usual candidate due to its long detection window. Depending on the drug and the frequency of use, substances can be detected in hair samples for up to 90 days after they have been consumed. Thus, the hair follicle drug test is useful for producing a long-term picture of a current or prospective employee’s drug use history.

For employers, this raises some important questions. Is the hair follicle drug test also effective at detecting a single use of a substance in the occasional or one-time user? Are hair tests alone sufficient for the purposes of a drug-testing program, or are other methods, such as urine drug testing, necessary in addition to hair tests?

To answer these questions, it will be helpful to understand how hair follicles record a person’s substance use. Each time a drug is used, regardless of the method, it enters the blood. The blood then carries the substance to all parts of the body, including the hair follicles. Many substances, such as morphine, cocaine, amphetamines, and nicotine, attach to the melanin in hair follicles. Each use or exposure results in a tiny amount of the substance attaching to the hair, where it can stay for up to three months.

This is useful when longer windows of detection are needed. However, because only a small trace of the substance remains in the hair after each drug use, it is not the most accurate test for detecting a single use of a substance.

For this reason, the most effective drug testing programs use a range of specimen types, depending on the purpose of each particular test. The hair follicle test, for example, is particularly useful for pre-employment screening, as it reveals whether the use of certain substances are a part of the person’s lifestyle. For the purposes of screening potential employees, this is more useful than just knowing whether or not they used shortly before their interview. A recent history of substance use is usually considered an indicator that the person is likely to use again when they are employed.

Drug testing programs are not just for screening potential hires, however. For other purposes, like post-accident testing, it is important to know whether the employee has used a substance recently. In this case, a urine test can provide more accurate results on the employee’s recent drug use. In cases where the employee is suspected to be under the influence of alcohol, an evidential breath test (EBT) can be used to indicate the current level of alcohol in the body.

What is a urine drug test?

A urine drug test is the most common method of drug testing. The employee’s urine is analyzed in a lab to detect evidence of substance use over the past few days or weeks. This test can detect a range of substances, including alcohol, amphetamines, barbiturates, benzodiazepines, cocaine, marijuana, methamphetamine, opioids, and phencyclidine (PCP).

There are two types of urine tests. Immunoassays work by detecting antigen-antibody complexes created by the body in response to certain drugs. Because it is the quickest and least expensive type of urine test, it is the most commonly used. However, there is a risk of false positive readings, where the test indicates the use of a drug when the employee has not, in fact, used.

Because of this, when an immunoassay reads positive for the use of a substance, the next step is typically to re-test the urine using a more accurate test called GC/MS. In this test, specialized equipment is used to identify substances in the urine. A false positive reading with a GC/MS test is much lower.

Where can my company order employee drug tests?

It is important to use a reputable and certified laboratory for your employee drug-testing program. Physicians Immediate Care can help you plan and deliver an employee drug-testing program that fits your needs and minimizes disruptions to your workflow. Contact us today to learn more about our drug testing services and how we can help keep your workplace safe and drug-free.