The Difficult Interpretation of a Hair Test Result from a 32-month old Child: Administration of Propranolol and Quetiapine or Contamination?

A 23-month old boy was brought to a medical center by his mother, as she noticed that the father has gripped him around the neck and this had left marks. As a result of this, a child protection medical examination was requested. However, there was a significant chronology of mental health issues in the mother. Among the mother's medications, quetiapine and propranolol were the more active. Given a consultant paediatrician was concerned that the boy was vulnerable and potentially has experienced neglect and physical harm, the local authority instructed a hair test to document possible poisoning. However, this occurred several months later, due to Court delays (postponed hearings and decisions) when the child was 32-month old. The laboratory received a strand of hair of the child (12 cm in length, light brown in color) and a strand of hair of the mother (> 20 cm in length, dark in color) with the request to test both specimens by segmentation (12 x 1 cm) for quetiapine, an anti-psychotic drug and propranolol, a β-blocker agent. After decontamination and segmentation, the specimens were incubated in borate buffer pH 9.5 and extracted by a mixture of ether/dichloromethane/hexane/isoamyl alcohol to test for the drugs, including norquetiapine by a specific LC-MS-MS method. The first 3 cm segments of the child's hair were free of drug, roughly corresponding to the period he was no more in contact with the mother. Propranolol tested positive in the other segments at 15 to 72 pg/mg, with a linear increase from the proximal to the distal end. This was also observed for quetiapine, with concentrations in the range 10 to 18 pg/mg. Norquetiapine was never identified in the child's hair. The following concentrations were observed in the mother's hair: 6028 to 10284, 910 to 4576, and 1116 to 6956 pg/mg for propranolol, quetiapine and norquetiapine, respectively. This confirmed that the donor was a long-term repetitive user of propranolol and quetiapine. The hair test results have indicated that the child was in contact with propranolol and quetiapine for a long period. It is not possible to put a temporal period for each segment, as the hair growth at the age of 32 months is not the same as for an adult (difference in the duration of the anagen period), nor to put any quantitative dosage or frequency of exposure (s) when interpreting the data. An increase of concentrations from root to tip was observed which is considered highly indicative of external contamination, with the older hair segments (those which are the more concentrated) being in contact for a longer time with contaminated items (hands of the mother, home items such as furniture, dishes, beddings, etc). Over-interpreting drug findings in hair can have very serious legal implications in child protection cases, particularly when no other toxicological test and no clinical report exist to support voluntary administration of drugs. Whatever the findings, a proper interpretation of hair test results is critical and should be done ideally with other information available, e.g. medical history, witness statements and the available circumstances of the matter. A single hair test should not be firmly used to discriminate long-term exposure to a drug.