Hair follicle drug testing frequently asked questions 2 Drugs in hair may be detectable for approximately 90 days, whereas drugs in urine are generally detectable for one to seven days or longer in chronic users and in oral fluid from five to 48 hours.
The simple answer is hair drug testing can go back as far as the hair shaft is long. So, if a 3cm section of hair provides an approximate 3-month overview, a 12 cm section of hair can offer an approximate 12-month profile.
No. Hair tests are designed to catch frequent users of drugs, one time use will not be enough drug metabolites in your hair to be above the cutoff levels which seem to vary slightly from state to state.
Although longer samples of hair can be tested for drug exposure over a longer period of time, a standard sample of hair from the scalp is 1.5 inches and provides information about approximately 90 days of past drug exposure.
Specificity of hair testing at standard laboratory cut-offs exceeded 90% for all drugs, but sensitivity of hair testing relative to self-report was low, identifying only 52.3% (127/243) of self-disclosed marijuana users, 65.2% (30/46) of cocaine users, 24.2% (8/33) of amphetamine users, and 2.9% (2/68) of opioid users.
Bleaching hair peroxide decreases the detectability of cocaine in user hair. Melanin–cocaine bonds are broken and cocaine is degraded into reaction products. Unbound cocaine and reaction products are washed out removing evidence of cocaine use.
Bleaching, dyeing, perming, and straightening can all impact a hair drug test result. This is because the chemicals used in these types of treatments can damage the hair shaft and alter the concentration of the drug.
Hair follicle drugs of abuse testing offers up to a 90-day window for detection of drug use and a convenient collection process that can be performed almost anywhere.
Hair drug testing and bleached hair
The drug compounds, metabolites, will be inside the hair as it grows. Bleaching the hair can remove between 40-80% of metabolites found in the hair strand. If multiple bleaching attempts are made a participant can remove all drugs from their hair.
Hair drug test collection
If the donor does not have head hair or if their hair is less than a ½ inch long, a specimen can be taken from other locations on the body. In order of preference, our collectors will cut the chest, underarm, leg, or facial hair to obtain a sample.
Up to 90 days can fail a hair follicle test.
Most drugs of abuse stay in the body for at least a few days after the last use and are traceable with urine tests. Opioids like heroin and oxycodone are detectable for between 1 and 3 days after last use. Stimulants including cocaine, meth, and ADHD medications are detectable for about 2 or 3 days.
The Timeline of Hair Follicle Testing
While a urine test typically has a detection time frame of 2-5 days, a hair follicle test can detect drug use as far back as 90 days. For this reason, it is considered a more reliable indicator of drug use than urine testing.
Most hair drug tests can detect heavy or regular use of certain illicit substances over the past three months. Your hair grows at a rate of about one-half inch per month from the scalp. The standard 1.5-inch sample taken near the root provides a snapshot of drug use over the past 90 days.
The use of a drug on one occasion only would not be expected to give rise to positive results as insufficient drug would be expected to accumulate in the hair to be detected above the cut off level. This is because almost all of the hair analysed would cover a time when drug use had not occurred.
How far back can a hair drug test detect drug use? Hair drug tests have the longest detection period, and can typically detect drug use for up to 90 days. Depending on the drugs used, a hair sample can sometimes help determine when drug use occurred and whether it's been discontinued.
How accurate are hair follicle drug tests? Hair follicle drug tests can determine whether a person has been using certain substances within the past 3 months . However, these tests cannot pinpoint the exact date of drug use because hair growth rates can vary widely among different people.
This is because it takes about 5-10 days for drug-containing hair to grow above the scalp. Will one night of drinking show up in a hair follicle test? No, a single night of drinking will not show up in a hair follicle test. However, regular and heavy alcohol consumption can be detected in hair samples.
While abstaining from drug use is the only surefire way to pass a hair drug test, awareness of the test's capabilities and limitations is essential for informed decision-making.
Hair drug testing on dyed or bleached hair may still be worthwhile. Any chemical treatment such as hair dye, bleach, chemical straightening and permanent waves can damage the hair. This damage may lead to some of the drugs that may be present, being leached out from the hair.