A 10-panel hair follicle test screens for ten of the most commonly abused drug classes, covering both street drugs and prescription medications. The standard panel detects cannabis, cocaine, opioids, amphetamines, benzodiazepines, barbiturates, phencyclidine (PCP), MDMA (ecstasy), methaqualone, and propoxyphene. Unlike urine tests that catch recent use, a hair test captures roughly 90 days of drug history in a single sample.
The 10 Substances on the Panel
The test is designed to cast a wide net across the drugs most likely to show up in workplace, legal, or clinical screening. Here’s what each category covers:
- Cannabis (marijuana, THC)
- Cocaine, including its breakdown product benzoylecgonine
- Opioids, such as heroin, morphine, and codeine
- Amphetamines, including methamphetamine
- Benzodiazepines, prescription sedatives like diazepam and alprazolam
- Barbiturates, older sedatives still occasionally prescribed
- PCP (phencyclidine), also called angel dust
- MDMA (ecstasy)
- Methaqualone (Quaaludes)
- Propoxyphene, a now-discontinued pain reliever
Some employers or agencies use expanded panels. A 12-panel test, for example, typically adds oxycodone and sometimes separates MDMA into its own category if it wasn’t already broken out. If you’re being tested for a specific job or legal requirement, the ordering party can customize which substances are included.
Why Hair Tests Cover 90 Days
Scalp hair grows at roughly half an inch per month. When you use a substance, your body metabolizes it and deposits traces of the drug and its breakdown products into the hair shaft through the bloodstream. A standard 1.5-inch sample, cut as close to the scalp as possible, therefore represents about three months of growth.
This is dramatically longer than the detection window for urine (typically 1 to 30 days depending on the substance) or blood and saliva tests (usually hours to a few days). It’s the main reason hair testing is favored for pre-employment screening and court-ordered monitoring: it reveals patterns of repeated use rather than just what happened last weekend.
One important nuance is that a drug won’t appear in your hair immediately after use. It takes roughly 7 to 10 days for new hair containing the drug to grow above the scalp where it can be collected. So hair testing has a blind spot for very recent use.
How the Sample Is Collected
The collector cuts about 90 to 120 strands of hair (roughly 100 milligrams) from the crown of the head, as close to the scalp as possible. The sample is small enough that it doesn’t leave a visible bald spot. It’s then sealed, labeled, and sent to a laboratory.
If you don’t have enough head hair, the collector can take body hair from the leg, chest, or underarm as a substitute. Body hair works, but it complicates the timeline. Body hair has longer periods of dormancy between growth cycles, which means the detection window is harder to pin down and can span well beyond 90 days. Labs prefer scalp hair whenever it’s available.
How the Lab Analyzes Your Sample
Testing happens in two stages. The lab first splits the hair sample into portions. One portion goes through an initial screening using an immunoassay, which is a quick, broad test that flags anything above a set threshold for each drug class. If this first screen comes back negative, testing stops there.
If the screen is positive for any substance, the lab runs a confirmation test on the second portion using a much more precise technique called mass spectrometry. This confirmation step identifies the exact drug and its concentration, eliminating false positives from the initial screen. A result is only reported as positive after both stages agree.
Can Hair Treatments Affect Results?
Yes, and significantly. Bleaching, dyeing, and perming all use harsh chemicals that damage the hair shaft, and that damage allows drug traces to leach out. Research comparing treated and untreated sections of the same hair found that cosmetic treatments reduced drug concentrations by 30% to over 60%, depending on the substance and the severity of the damage. Bleaching caused larger drops than dyeing alone.
Cocaine and its metabolites, codeine, and the heroin marker 6-acetylmorphine all dropped by 40% to 60% in treated hair. Morphine levels fell by more than 60%. THC and nicotine showed smaller decreases around 30%. The more damaged the hair, the greater the drug loss. This means heavily processed hair could potentially produce a false negative, though labs are aware of this limitation and may note visible damage in their report.
Environmental Exposure vs. Actual Use
A common concern is whether being around someone who smokes marijuana or crack cocaine could cause you to test positive. Labs wash hair samples before analysis to strip away surface contaminants, but these decontamination procedures aren’t standardized across the industry, and the washing process itself can sometimes push drugs from the surface into the hair shaft.
A more promising approach, developed by researchers funded by the National Institute of Justice, focuses on testing for specific drug metabolites rather than the parent drug. When your body processes a drug, it creates breakdown products called conjugated metabolites that only form through internal metabolism. These metabolites wouldn’t be present in hair from someone who was merely in the same room as drug smoke. If the lab detects these metabolites, it’s strong evidence of actual ingestion rather than passive exposure. This technique is still gaining adoption, but it represents a meaningful improvement in distinguishing users from bystanders.
What a Positive Result Means in Practice
A positive 10-panel hair test tells the requesting party that you used one or more of the tested substances at some point during the roughly 90-day window. It does not reveal how often you used, how much you took, or whether you were impaired at any particular time. It’s a yes-or-no answer for each drug class, not a measure of severity.
If your result comes back positive and you believe it’s wrong, most testing protocols allow you to request a retest of the original sample or provide a new sample. Prescription medications like benzodiazepines, opioids, or amphetamines (prescribed for ADHD, for instance) can trigger positive results, so you’ll typically have the opportunity to provide documentation of valid prescriptions to a Medical Review Officer before the result is finalized and reported to your employer or the court.