Compared with traditional biological samples such as blood and urine, hair samples have unique advantages. For example: long time limit for detection, comprehensive drug abuse information, anti-corruption, easy to take, preserve and repeat sampling. The most prominent advantage is that the detection time is long, and the length of the hair can reflect the medication for several weeks to several months. The time limit for drug detection in body fluids is short (the last 3-5 days after administration, the marijuana is slightly longer), which is suitable for the detection of drug abuse in short-term. The combination of the detection of body fluid and hair can comprehensively evaluate the drug abuse of the subject and meet the needs of forensic, clinical and scientific research.
After 7 days of drug use, the drugs in the blood and urine are basically metabolized, but the drug components can still be detected in the hair. And the drug component can be stably present in the hair for a long time (several years), not only in the hair, but also in the leg hair, pubic hair, and mane.