According to HomeHealthTesting.com, blood nourishes the hair as it grows. Drugs in the blood enter the hair and embed in the hair shaft. It takes one week after drug use for the drug-affected hair to grow above the scalp. Hair samples may provide evidence of the following drugs: phencyclidine, cocaine, marijuana, opiates, methamphetamines, amphetamines and Ecstasy.
Phencyclidine
Phencyclidine, also called "angel dust" or PCP, produces agitation, impaired coordination, difficulty speaking and acute psychosis, according to "Harrison's Principles of Internal Medicine." In a study published in the "American Journal of Psychiatry," as stated by Dr. John Sramek, hair analysis detected past PCP use in 6 out of 31, or 19 percent, of psychiatric patients and in 5 of 16 patients, or 31 percent, of patients selected by the admitting psychiatrist to rule out PCP; in contrast, standard testing for PCP using blood and urine did not detect any positives.
Cocaine
Cocaine, a stimulant and local anesthetic, produces mood enhancement and increases heart rate and blood pressure. It can cause seizures, headache and stroke, according to "Harrison's Principles of Internal Medicine."
According to NCJRS.gov, hair analysis provides a better indication of cocaine use over extended periods of time and can more accurately identify a chronic drug user. Furthermore, drugs and drug metabolites remain sequestered in the hair shaft indefinitely, thus providing detection during a much larger "window."
Marijuana
Marijuana contains over 400 compounds, including the active compound tetra-hydrocannabinol, according to "Harrison's Principles of Internal Medicine." Intoxication consists of mild euphoria, relaxation and impairment in thinking and concentration.
According to NCJRS.gov, the hair assay for marijuana approximates the urine assay in detection. It does not show the enhanced detection capability of cocaine assays, but this is expected, since marijuana may be detected in urine for a relatively long time.
References
- Home Health Testing: Hair Drug Test
- "Harrison's Principles of Internal Medicine"; Dennis Kasper, M.D.; 2005
- American Journal of Psychiatry; Hair Analysis for Detection of Phencyclidine; John Sramek, M.D., Aug 1985
- Hair Analysis As a Drug Detector
