Most drugs can be detected in the hair for up to 90 days. The hair is unique among parts of the body that can be tested for drugs. Unlike urine, blood and saliva, drugs do not temporarily deposit in hair. Instead, drugs stay in the hair for the life of the hair.
To help standardize testing, many labs only collect hair within 1.5 inches of the scalp. This means that they usually cannot detect drug usage more than 90 days in the past. The average hair follicle test is just for the past three months of your life.
Note:Alcohol, LSD (lysergic acid diethylamide), digoxin, lithium, THC (tetrahydrocannabinol), and some benzodiazepines, opiates, amphetamine- type stimulants, and most drugs of abuse are not detected by this procedure. For these drugs, the specific confirmation tests should be ordered.
For example, a segment of head hair 1.5 inches from the scalp will represent up to 90 days of drug use. For very long hair, segmental analysis can give a broader timeline. Body hair can represent anywhere from a few months to a year of drug use, though this varies between individuals.
The length of time a failed drug screen stays on a record depends on the employer and the type of record. Records from a failed DOT drug test remain in the Drug and Alcohol Clearinghouse Database for five years or until a person resolves the violation through the return-to-duty process and follow-up testing.
When your urine specimen for a drug test comes up diluted, you drank too much water in advance of the test. You should be careful not to overconsume fluids prior to a drug test. An extra glass of water is about all you need. If you drink too many fluids, then you will more than likely end up with a diluted specimen.
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.
Urine tests can detect drugs from two to 28 days, while hair follicle tests can go back up to 90 days or more. Blood tests provide a shorter detection window but are highly accurate for recent use. Saliva tests offer a balanced approach, detecting drug use from a few hours to a few days of detection.
Typically ingesting 1-2 liters or more within an hour of testing is sufficient to dilute most specimens for a 2–6 hour period. Diuretics such as caffeine and cranberry juice and some medications, including water pills may cause diluted urine samples.
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.
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.
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.
Hair Follicle Drug Testing FAQ
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.
Because drugs remain in strands of hair for months longer than they do in the bloodstream, drug tests based on hair are more robust across time and can provide evidence of drug use in the more distant past. Although neither test can reveal the quantity of drugs consumed, they can identify the drugs present.
Safe and Effective Ingredients
The Old Style Aloe Toxin Rid Shampoo and the Zydot Ultra Clean Shampoo contain penetrating cleansing agents that are gentle on the hair while effectively removing residual buildup, environmental pollutants, chemicals, chlorine, hard water minerals, and hair-dulling impurities.
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.
The consumption of drugs will always show accurately when tested from our hair, whether that be head hair or body hair. Although it can't be covered up, there are a few popular myths that have people thinking the opposite. For example, users cannot use a special shampoo to cover it up.
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.
Specimen validity testing (SVT) is performed on a urine drug screen specimen to detect substitution, adulteration, or dilution. See the Drugs of Abuse Reference Guide for additional information on SVT.
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.