Abstract：
Nails are a keratinized matrix that has been proposed as an alternative to hair to evaluate long-term and retrospective consumption of drugs of abuse and pharmaceuticals. This matrix has been gaining interest in recent years, with new studies focusing on the analysis of fingernails and/or toenails for different substances. However, nails and hair present differences in structure, growth, and incorporation pathways that may affect drug incorporation and analysis and complicate the interpretation of the results. To better understand the results in nail samples, a comparison of concentrations found in hair, fingernails, and toenails has been described in the literature for some drugs. This review unifies the results found in the literature, with special interest on studies that report paired samples from the same individuals. Differences between fingernail and toenail samples, as well as proposed cut-offs in nails, are also discussed. Definite conclusions can be reached for some drugs, but, in general, more standardized studies are needed to better understand nail results.
摘要：
指甲是一种角质化基质，已被提议作为头发的替代品，以评估长期和回顾性的滥用药物和药物的消耗。这个矩阵近年来越来越受到人们的关注，新的研究重点是分析不同物质的指甲和/或脚趾甲。然而,指甲和头发在结构上存在差异，增长,以及可能影响药物掺入和分析并使结果解释复杂化的掺入途径。为了更好地了解指甲样本的结果，在头发中发现的浓度比较，手指甲,和脚趾甲已经在文献中描述了一些药物。这篇综述结合了文献中的结果，对报告来自同一个体的配对样本的研究特别感兴趣。手指甲和脚趾甲样品之间的差异，以及拟议的指甲切割，也讨论了。对于某些药物可以得出明确的结论，但是,总的来说,需要更多的标准化研究来更好地了解指甲结果.
