Human hair as a diagnostic tool in medicine.

Hair analysis has been used in the past as a method to explore environmental exposure to chemicals, toxins or drug ingestion, with wide applications in forensic science, environmental studies, anthropology and medicine. Although not a conventional sample type, hair offers significant advantages over traditional biospecimens, such as blood or urine. These include its stability, non-invasive nature and ease of collection and handling, as well as its ability to provide a "fossilized" record of a person's health or living conditions. These unique characteristics, along with advancements in analytical techniques have enabled hair analysis as a promising tool for the development of new biomarkers for both prognostic and diagnostic purposes in a range of medical conditions. The new developments in hair analysis add to its recognized diagnostic value in fields such as toxicology and pharmacology. In this review, we summarize recent data, ongoing developments and emerging possibilities of hair analysis as a scientific and diagnostic tool.