A hair follicle test is a drug screening method that analyzes the cortex or inner part of the hair to reveal drugs and drug metabolites, the presence of which exposes drug use. Hair tests are highly accurate and can reveal patterns and history of drug use. Occasional, and even one-time drug use can be revealed by a hair test. Various factors determine the outcome of a hair follicle test.
Hair Sample
A hair sample of at least sixty milligrams is required for a hair test drug screen. This weight generally represents approximately 100 strands of hair. Hair color has no relation to the outcome of the test. Body hair may be used for the sample if hair from the head is too short; however, because body hair grows more slowly than hair from the head, test results tend to be less comprehensive. Typical hair samples are one and a half inches long, taken from as close to the scalp as possible.
Time Period
Standard hair tests cover a period of approximately 90 days, which is why the hair sample is generally an inch and a half in length. Hair grows at an approximate rate of one inch every thirty days. A hair sample composed of longer strands of hair will reveal the possibility of drug use for a longer period.
Confirmation
Hair tests that yield a positive result, indicating drug use, are confirmed by a gas chromatography/mass spectrometry (GC/MS) method. A gas spectrometry device vaporizes the sample and displays its components. Mass spectrometry identifies the components by electrically charging them and separating them according to their electrical charges. When these two methods are used in tandem the results are highly accurate.
Drugs
The Substance Abuse and Mental Health Services Administration of the United States federal government requires that standardized drug screens, including hair tests, screen for five types of drugs. The five types of drugs, known collectively as the SAMHSA-5 are amphetamines, cocaine, marijuana, opiates, and phencyclidine (PCP). Other drugs that may be detected by a hair test are certain types of antidepressants, mescaline, methadone, and nicotine.
Metabolites
When drugs are ingested they enter the bloodstream, which feeds hair growth; therefore, drugs and drug metabolites can be found within the cortex of the hair. Drug metabolites are compounds produced by the body when it processes drugs. Certain drugs have corresponding metabolites. It takes approximately five days after use for drugs and drug metabolites to appear in the hair above the scalp.
External Exposure
Drug metabolites are only present in the hair as a result of consumption. External exposure to drugs, such as second hand marijuana smoke, will not yield a positive hair test.
Accuracy
Because hair tests examine the cortex of the hair, they are accurate and resistant to contamination. Washing the hair, even with detoxifying shampoo, only cleans the outer part of the hair.
Related posts
If a person's possible use of drugs comes into question, you would need to look no further than the hair on her head for answers. Even though drugs may leave a person's bloodstream, the evidence o...
There are many different methods that can be used to detect the use of drugs. Some methods are extremely expensive while others are relatively cheap. Hair and urine testing have become the most po...
Hair drug tests can determine the past 90 days of a person's drug use.Hair drug testing analyzes 90 to 120 strands to determine the presence of drugs. Drugs embed themselves into the hair shaft, w...
Drug metabolites may be present in the hair indefinitely, though typical hair drug tests only test for an approximate period of the last three months.FunctionWhen drugs are ingested and processed...
Drug tests are becoming standard in the hiring and retaining of employees in businesses throughout the United States. The most frequently done and cost effective drug test is a urine test; however...
