Latest Posts
Drug positivity rates continue at historically high levels
Marijuana positivity continues double-digit increases to keep overall drug positivity at historically high levels, according to the latest Quest Diagnostics Drug Testing Index.
Ask the Experts: Hair drug test collections
The amount of hair needed for a hair drug test is approximately 100 milligrams made up of the first 1-½ inches from the root end. The hair is typically cut from the crown of the back of the head in a manner where it will not be as noticeable. Learn more about hair drug test collections.
Ask the experts: Secondhand marijuana smoke
Can you fail a drug test from secondhand smoke? There are no published, peer-reviewed studies to date that indicate someone would test positive on a drug test due to incidental exposure of marijuana smoke. Learn more from Dr. Barry Sample, Quest Diagnostics.
Thwarting drug test cheaters
There are safeguards to help employers prevent a job applicant or employee who uses drugs from cheating or altering a drug test. Learn more.
Ask the experts: Hair testing vs. hair follicle testing
What is the difference between hair drug testing and hair follicle drug testing? We asked a Quest expert to explain.
Celebrating Lab Week
Every April, we honor our lab professionals during Lab Week. Their work makes helps to keep our workplaces safe and drug-free.
Challenging the poppy seed defense
A Quest Diagnostics study helps to answer the question: Can eating poppy seeds produce a positive drug test for a job applicant or employee?
Ask the experts: Effects of hair treatments on drug test results
Our scientific expert, Dr. Barry Sample, answers the question: Can products and treatments affect hair drug test results?
Ask the experts: The life of a drug testing specimen
Our labs handle more than eight million drug testing specimens yearly while maintaining an excellent track record of reliability and accuracy.
Common questions about hair testing
An expert from Quest Diagnostics answers some of the most common questions about hair drug testing.
