In present-day scenario hair has become a vital biological sample, substitute to the usual samples blood and urine which are found at the crime scene, for drug testing in the different fields like forensic toxicology, clinical toxicology and clinical chemistry. Furthermore, hair-testing is now extensively used in workplace testing and at legal cases, historical research etc. Hair structure and the mechanisms of drug incorporation into it are discussed. The usual training and withdrawal methods as well as the analytical techniques of hair samples are offered. The conclusions of hair analysis have been reviewed for the following categories: drugs of abuse (opiates, cocaine and related, amphetamines, cannabinoids), benzodiazepines, official drugs, pesticides and biological pollutants, doping agents and other drugs or substances. …show more content…
One of the important aspect of using hair as an evidence to draw conclusion on the drug quantity used by any person over urine is that hair sample gives long term information about the individual’s drug use. The growth of head hair occurs at rate of approximately 1.3 cm/month. Subsequently, by taking the specimen the section of hair parallel to a time frame, hair analysis can disclose drug usage by that individual from over a past week to years. The hair strand even cannot be adulterated like a urine or blood sample and moreover can be stored for a long duration than the other biological samples without refrigerating them and this counts another advantage of hair sample over other biological samples. Its extensive range of detection and permanent record of drug being taken make hair investigation far effective than the unannounced urinalysis for the identification of even infrequent