SoylentNewsby martyb on (#4Z475)
hubie writes:Fingerprints contain a variety of substances that originate from both within the body and from what is on the surface of the skin, and as such they have the potential to convey a lot more information than just their ridge details. Forensic research has looked into fingerprint residue to determine whether illicit drugs were handled, and other research has investigated changes in fingerprint chemistry after drugs were ingested. Although it is possible to detect the primary metabolite of cocaine, benzoylecgonine (BZE), in fingerprints, it hasn't been possible to determine whether the presence of BZE residue was the result of handling or using the drug.Researchers from the UK and Republic of Ireland investigated the levels of cocaine and BZE found in fingerprints at various time intervals after contact with cocaine powder and with street cocaine. They compared them with fingerprints taken from a variety of patients attending a drug rehabilitation clinic, as well as non-drug users. In a paper in the open access journal Scientific Reports they showed that it is possible to distinguish between contact and ingestion of cocaine from a fingerprint, if (and only if) the fingerprints were obtained after the person had washed their hands.Paper Abstract:The finding that drugs and metabolites can be detected from fingerprints is of potential relevance to forensic science and as well as toxicology and clinical testing. However, discriminating between dermal contact and ingestion of drugs has never been verified experimentally. The inability to interpret the result of finding a drug or metabolite in a fingerprint has prevented widespread adoption of fingerprints in drug testing and limits the probative value of detecting drugs in fingermarks. A commonly held belief is that the detection of metabolites of drugs of abuse in fingerprints can be used to confirm a drug has been ingested. However, we show here that cocaine and its primary metabolite, benzoylecgonine, can be detected in fingerprints of non-drug users after contact with cocaine. Additionally, cocaine was found to persist above environmental levels for up to 48 hours after contact. Therefore the detection of cocaine and benzoylecgonine (BZE) in fingermarks can be forensically significant, but do not demonstrate that a person has ingested the substance. In contrast, the data here shows that a drug test from a fingerprint (where hands can be washed prior to donating a sample) CAN distinguish between contact and ingestion of cocaine. If hands were washed prior to giving a fingerprint, BZE was detected only after the administration of cocaine. Therefore BZE can be used to distinguish cocaine contact from cocaine ingestion, provided donors wash their hands prior to sampling. A test based on the detection of BZE in at least one of two donated fingerprint samples has accuracy 95%, sensitivity 90% and specificity of 100% (n = 86).Jang, M., Costa, C., Bunch, J. et al. On the relevance of cocaine detection in a fingerprint. Sci Rep 10, 1974 (2020). https://doi.org/10.1038/s41598-020-58856-0Original SubmissionRead more of this story at SoylentNews.