Kintz Pascal, Ameline Alice, Eibel Aude, Gheddar Laurie, Feisthauer Emilie, Geraut Annie, Berthelon Laurent, Farrugia Audrey, Raul Jean-Sebastien
Institut de Medecine legale, 11 rue Humann, 67000 Strasbourg, France.
Curr Pharm Biotechnol. 2017;18(10):791-795. doi: 10.2174/1389201019666171129180206.
Hair has been suggested since the middle of the 90's to be a suitable matrix to document repetitive exposure to cannabis. Because it is possible to detect Δ9-tetrahydrocannabinol (THC), cannabinol (CBN) and cannabidiol (CBD) in cannabis smoke, the identification of the metabolite, 11-nor-Δ9-tetrahydrocannabinol carboxylic acid (THC-COOH) has been considered to allow the discrimination of active use.
Although the identification of an active compound in a child's hair shows contamination of the local environment, it is a challenge to discriminate between hair incorporation after ingestion or inhalation and environmental external deposition from dust, smoke, or even contaminated surfaces by hand contact. However, it is particularly important in case of children to correctly interpret the data, particularly for a realistic assessment of the health risk. We present here a series of hair tests for cannabis where the interpretation was almost impossible to establish.
Hair specimens were collected during the autopsy of the 12 children, aged 2 to 24 months, either deceased from shaken baby syndrome (SBS, n=4), mechanic asphyxia (MA, n=1) or sudden infant death (SID, n=7) during January 2015 to April 2017. After decontamination, the hair specimens were tested for THC, CBN and CBD and THC-COOH. The whole length of hair was submitted to analysis.
The amount of hair from children can be as low as 8 mg. This may affect the limit of quantitation of all drugs, but particularly THC-COOH. Eight from twelve hair tests were positive for cannabis markers, i.e. THC (39 to 1890 pg/mg, n=8), CBN (< 5 to 1300 pg/mg n=8), CBD (10 to 2300 pg/mg, n=8) and THC-COOH (not detected to < 0.5 pg/mg, n=5). In 4 cases from 8 positive findings, it was not possible to test for THC-COOH (not enough material).
Establishing a window of detection when testing for drugs in young children is a very complicated task. Hair from children is finer and more porous in comparison with adult (the risk of contamination from sweat and environmental smoke is higher than in adults). The final interpretation of cannabinoid findings in the children's hair is very complicated as this can result from in utero exposure (although none of the mother admitted cannabis use during pregnancy), oral cannabis administration by the parents to achieve sedation, close contact to cannabis consumers (hands, bedding, dishes) and inhalation of side-stream smoke. Over-interpreting cannabis findings in hair can have very serious legal implication in child protection cases. Practicing scientists have the responsibility to inform the child protection authorities, courts, etc. about these limitations.
自20世纪90年代中期以来，头发就被认为是记录大麻反复接触情况的合适基质。由于在大麻烟雾中能够检测出Δ9-四氢大麻酚（THC）、大麻酚（CBN）和大麻二酚（CBD），因此对代谢物11-去甲-Δ9-四氢大麻酚羧酸（THC-COOH）的鉴定被认为有助于区分是否有实际使用大麻的情况。
虽然在儿童头发中鉴定出活性化合物表明当地环境受到污染，但要区分摄入或吸入后头发中的大麻成分与灰尘、烟雾甚至手部接触污染表面导致的环境外部沉积情况具有挑战性。然而，对于儿童而言，正确解读数据尤为重要，特别是为了对健康风险进行实际评估。我们在此展示了一系列大麻毛发检测案例，这些案例几乎无法进行解读。
在2015年1月至2017年4月期间，对12名年龄在2至24个月的儿童进行尸检时采集毛发样本，这些儿童分别死于摇晃婴儿综合征（SBS，n = 4）、机械性窒息（MA，n = 1）或婴儿猝死（SID，n = 7）。去污后，对毛发样本进行THC、CBN、CBD和THC-COOH检测。整根头发都进行了分析。
儿童的毛发量可能低至8毫克。这可能会影响所有药物的定量限，尤其是THC-COOH。12次毛发检测中有8次大麻标志物呈阳性，即THC（39至1890皮克/毫克，n = 8）、CBN（<5至1300皮克/毫克，n = 8）、CBD（10至2300皮克/毫克，n = 8）和THC-COOH（未检测到至<0.5皮克/毫克，n = 5）。在8例阳性结果中的4例中，无法检测THC-COOH（材料不足）。
对幼儿进行药物检测时确定检测窗口是一项非常复杂的任务。与成人相比，儿童的头发更细且孔隙更多（汗液和环境烟雾污染的风险高于成人）。儿童头发中大麻素检测结果的最终解读非常复杂，因为这可能源于子宫内接触（尽管没有母亲承认在孕期使用大麻）、父母为使孩子镇静而口服大麻、与大麻使用者密切接触（手、被褥、餐具）以及吸入侧流烟雾。在儿童保护案件中，对头发中大麻检测结果过度解读可能会产生非常严重的法律后果。执业科学家有责任将这些局限性告知儿童保护当局、法院等。
