ABSTRACT
The Devil is in the details, and there are many details concerning the analysis of hair for drugs of abuse and the interpretation of the analytical result. Several controversies have arisen over the past few years surrounding many of these details. The controversies have focused on two broad areas: (1) the mechanisms for appearance in hair and binding to hair of drugs of abuse and (2) removal of external contamination. The conclusions reached in these two areas and the weight given to the scientific facts greatly color the interpretation of any hair analysis result. This review outlines the historical evidence accumulated in these two areas of research and discusses how the interpretation of these data has led to two disparate models of incorporation and removal of drugs from hair. Also, new data are presented to clarify areas of controversy. An understanding of the data and its interpretation is critical to the proper application of hair analysis results.*
