During the hair growth process, the drug in the blood enters the hair follicles of the scalp from the blood and is fixed in the hair by keratin. Hair containing drugs can grow from the surface of the scalp in about 3-5 days. The time and dose of drug abuse can be inferred by extracting and detecting the drug content in the hair.
The traditional blood, urine and other drugs in the sample are usually metabolized after 7 days of medication, and the detection time is relatively short (marijuana has a longer time in the last 3-5 days), so it is suitable for short-term drug detection. The pharmaceutical ingredients in the hair sample can be stored for several months or even longer. It has a series of unique advantages such as long detection time, good stability, anti-corruption, easy collection, storage and repeated sampling, and difficult replacement. . Among them, the most prominent advantage is the long detection time. Depending on the length of the hair, it can reflect the medication situation of several weeks to several months.
At present, the analysis of drugs in hair has been gradually applied in forensic and clinical toxicology analysis, and its role in drug abuse identification has been confirmed and recognized.
The quick and simple extraction method only takes 1 minute and does not require any external equipment. The pretreated sample solution is directly added to the test card, and the result can be read with a fluorescence immunoassay after 5 minutes of reaction.