Columbus Health and Wellness Testing
Hair Follicle Testing Questions and Answers
Learn more about hair drug testing, detection windows, sample collection, laboratory procedures, and what to expect from the testing process.
Frequently Asked Questions
Understanding Hair Drug Testing
Have questions about hair drug testing? Explore the answers below to learn about the testing process, sample requirements, detection periods, and laboratory procedures.
Testing Basics & Detection Windows
1What is hair drug testing?
Since hair growth is supplied by the bloodstream, the ingestion of drugs of abuse may be detected by analyzing a small hair sample. Testing measures drug molecules incorporated into the hair shaft. Laboratory washing and testing procedures are used to help distinguish drug use from external contamination.
Hair testing is generally more resistant to common attempts at tampering than some other testing methods. Results can vary depending on the substance, the test method, and the laboratory procedures used.
3What time period does a standard test cover?
A standard head-hair test typically evaluates approximately 90 days of potential drug use. The sample is generally collected as close to the scalp as possible, and the most recent 1.5 inches of suitable hair are commonly tested.
The actual period represented can vary with hair growth, the collection location, and the laboratory's testing protocol.
5How fast does head hair grow?
Head hair grows approximately 1.3 centimeters, or one-half inch, per month on average. Growth rates vary among individuals, so the timeframe represented by a hair test is an estimate rather than an exact calendar record of drug use.
7How does hair testing compare to urinalysis?
The primary differences are the detection window and the collection and testing procedures.
Urine testing generally detects many drugs over a shorter period, often a few days, although the actual window depends on the substance, frequency of use, individual factors, and test sensitivity. A standard head-hair test may provide a much longer retrospective window, commonly around 90 days.
Hair testing also offers a collection method that is generally less susceptible to certain forms of specimen substitution or adulteration. However, no testing method is immune to every limitation, and hair testing cannot establish the exact time of use or current impairment.
The appropriate method depends on the purpose of the test, the substances being assessed, and the applicable testing requirements.
8How soon after use can a drug be detected in hair?
It generally takes approximately four to five days for newly grown, affected head hair to emerge above the scalp after drug use. Detection timing varies with individual hair growth and the substance involved.
Body hair grows differently from head hair and generally cannot be used to determine a precise timeframe of drug use.
9What is the shortest time period that can be accurately evaluated?
A half-inch head-hair sample may represent approximately one month of growth, although the actual period varies. A laboratory must determine whether the sample length and amount are suitable for the requested test.
Body hair may be used when head hair is too short, but its different growth cycle makes the timeframe represented less precise. The supplied laboratory information describes body-hair testing as potentially representing approximately one year.
10Can tests be run on people with little or no head hair?
Hair may be collected from multiple areas of the head and combined when the collection protocol permits. Body hair may also be an option if there is insufficient head hair.
If no suitable hair can be collected, another testing method, such as urine testing, may be considered depending on the testing requirements.
11Does body hair give the same type of results as head hair?
Body hair can be used to test for many of the same drug classes, subject to the laboratory's methods and requirements. However, body hair grows and cycles differently from head hair.
As a result, body-hair testing may reflect a broader and less precisely defined period of potential drug use. The timeframe should be interpreted according to the laboratory's guidance.
Drugs Tested & Test Results
2What drugs are included in a standard hair drug test?
The standard five drug classes described in the supplied laboratory information are:
- Cocaine: Cocaine and benzoylecgonine
- Marijuana: Cannabis-related analytes
- Opiates: Codeine, morphine, and 6-monoacetylmorphine
- Amphetamines: Amphetamine, methamphetamine, and, where included in the panel, MDMA (Ecstasy)
- Phencyclidine: PCP
The substances included in a particular test depend on the panel ordered. Confirm the current panel and applicable requirements with the laboratory.
13How does Omega Laboratories establish its cutoff levels?
Cutoff levels are established according to the laboratory's testing procedures, applicable standards, and the analytical methods used. The supplied information states that Omega Laboratories follows industry-accepted cutoff levels based in part on detection capabilities for confirmatory testing such as gas chromatography/mass spectrometry (GC/MS).
Current cutoff levels should be confirmed directly with the laboratory for the specific test panel.
14Does Omega Laboratories perform GC/MS confirmation of all positive hair results?
The supplied laboratory information states that specimens screening positive for the five standard drug classes—opiates, PCP, methamphetamine, cocaine, and marijuana—receive confirmatory testing using GC/MS.
Confirm the current confirmation procedures with the laboratory, as testing methods and panels may change.
15Can over-the-counter medications affect hair test results?
Some substances can potentially cross-react during an initial screening test, which may produce a presumptive positive result. An initial screening result is not necessarily a final positive result.
The supplied Omega Laboratories information states that positive screens for methamphetamine, opiates, PCP, cocaine, and marijuana are confirmed using GC/MS to help distinguish the target substances from potential cross-reacting substances.
16How effective is hair testing in detecting drug use?
Hair and urine testing have different detection windows, and studies have found that hair testing may identify drug use that is not detected by urine testing performed at a different time.
The original laboratory material cites studies in which hair testing identified four to eight times as many users as urinalysis. That figure should be verified against the original studies before being used as a current, general claim, since results depend on the study population, substances tested, and testing protocols.
17Can external exposure to marijuana or crack smoke affect hair test results?
External exposure is an important consideration in hair drug testing. Laboratories use appropriate specimen preparation and analytical procedures to help distinguish environmental contamination from drug use.
The supplied Omega Laboratories information states that, for marijuana analysis, its method detects the metabolite THC-COOH, which is produced by the body. Confirm the laboratory's current analytes and interpretation procedures for the specific test ordered.
22What other drugs can be tested through hair analysis?
Depending on the laboratory's available methods, specialized hair analysis may be available for additional substances, potentially including nicotine, methadone, certain benzodiazepines, tricyclic antidepressants, and mescaline.
Availability, cutoff levels, interpretation, and the relationship between exposure and measured concentrations differ by substance. Contact the laboratory to determine which specialized tests are currently available.
23Does hair color affect test results?
Hair color is influenced in part by melanin, and differences in hair characteristics may be relevant to the interpretation of some hair drug tests. The significance depends on the substance, the analytical method, and the testing circumstances.
For questions about a particular test or result, consult the laboratory about its current procedures and interpretation guidelines.
Sample Collection & Handling
6How much hair is needed?
The amount required depends on the testing method and the thickness of the hair. The supplied laboratory information describes a sample of approximately 40 milligrams, or roughly 90 to 120 strands, for a standard screen with confirmation testing.
The collector will determine whether enough suitable hair has been obtained for the test being performed.
12Can hair collected from a brush be used?
Hair collected from a brush is generally not accepted for testing that requires documented specimen identity and chain of custody.
The supplied Omega Laboratories information specifies use of its hair collection kit and requires the test subject to initial the sample collection pouch to help certify the sample's authenticity. Follow the current laboratory collection instructions for the test being ordered.
20What happens to excess hair that is not tested?
The supplied Omega Laboratories information states that unused hair from the relevant collection period is stored in the chain-of-custody sample acquisition pouch.
According to that information, negative specimens are stored for three months and positive specimens for one year. Confirm current specimen retention and storage policies directly with the laboratory.
Laboratory Standards & Procedures
4Are hair testing laboratories required to have FDA approval?
FDA approval and laboratory accreditation are different things. The FDA's role in workplace drug testing laboratories is not the same as its role in regulating medical products and other products within its authority.
The original laboratory information identifies Omega Laboratories as holding College of American Pathologists (CAP) accreditation. Verify the laboratory's current accreditation status and applicable testing requirements before relying on this information.
18Is Omega Laboratories' internal chain of custody comparable to a urine testing laboratory's procedures?
Chain of custody documents the handling of a specimen from collection through laboratory processing. The supplied Omega Laboratories information states that its internal chain-of-custody procedures are modeled on federal guidelines, including those associated with SAMHSA, and standards used by accredited organizations such as CAP.
Follow the laboratory's current procedures for the specific testing program and intended use of the results.
19How long are test reports kept on file?
The supplied Omega Laboratories information states that test reports are retained for two years or for a period required by law. Retention periods may vary based on the applicable program, contract, and legal requirements, so confirm the current policy with the laboratory.
21What experience does Omega Laboratories have with expert witness testimony?
The supplied laboratory information states that Omega Laboratories' forensic experts have qualified as expert witnesses in Ohio, New York, California, Texas, Nevada, Oklahoma, Alabama, and Arizona, in more than 250 civil, criminal, and superior court trials.
These historical figures and jurisdictional details should be confirmed with Omega Laboratories before publication.
Have more questions about hair drug testing? Contact Columbus Health and Wellness Testing for information about available testing services, collection procedures, and the next steps for arranging a test.