Potential and limitations of alternative specimens in doping control.

Alternative specimens (e.g., hair and saliva) are well established in forensic toxicology and provide significant benefits as noninvasive, inexpensive alternatives to blood with access to improved long-term retrospection. Based on these experiences, the question of potential applications and limitations of alternative specimens in doping control arose. Compounds prohibited at all times (e.g., clenbuterol, β(2) agonists, estrogen-receptor modulators) may be successfully tested and clearly interpreted in alternative specimens. In contrast, prohibition of certain compounds in sport are limited to time ranges (e.g., stimulants are only prohibited in-competition), dosages or administration routes (e.g., systemic uptake of glucocorticosteroids). This cannot be properly differentiated by semiquantitative tests (e.g., hair analyses), but may be distinguished in saliva. Similarly, proof of external administration of endogenous steroids (e.g., testosterone) only seems to be achievable by quantitative analysis of saliva. Moreover, the retrospective monitoring of the relevance of social drugs or upcoming (unapproved) substances represents promising applications of hair tests in doping control.