Hårtest

Hårtest, or hair testing, is an analytical technique that uses hair samples to detect chemical substances or elements that have been incorporated into hair shafts. In Swedish usage, hårtest commonly refers to drug testing, toxin screening, or nutritional/toxicological analysis. Hair can reflect exposure over weeks to months, depending on hair length and growth rate, roughly 1 cm per month for scalp hair.

Procedure typically involves collecting a small amount of scalp hair with consent, labeling and storing the sample, and performing a cleaning protocol to remove surface contaminants. The hair is then cut into segments and analyzed with methods such as gas chromatography–mass spectrometry (GC-MS) or liquid chromatography–tandem mass spectrometry (LC-MS/MS) for drugs and metabolites, or inductively coupled plasma mass spectrometry (ICP-MS) for metals and minerals. Segmental analysis can provide a timeline of exposure, while whole-hair analysis offers an overall exposure estimate. Laboratories often follow strict chain-of-custody and quality control procedures, and results are reported in concentration units (for example, ng/mg).

Applications of hårtest include forensic toxicology, where drug use or toxin exposure over extended periods may be relevant to investigations or legal cases; clinical toxicology and occupational health, for monitoring heavy metals such as lead or mercury; and nutritional or environmental health studies to assess mineral status or pollutant exposure. Hair analysis can also be used in anthropology and archaeology to study historical exposure patterns.

Advantages include a relatively long detection window, non-invasiveness, and the ability to reflect historical exposure. Limitations involve potential external contamination, variability in hair growth and cosmetic treatment affecting results, and the need for careful interpretation within context. Standardization and interpretation practices vary, and results are usually corroborated with other evidence or matrices. Ethical considerations and privacy concerns are also part of hair-testing discussions.