Breaking the paradigm of stressful blood draws and embarrassing urine sampling, a new drug testing platform first developed by chemists at the University of East Anglia (UEA) can detect the use of four major drug classes in just 10 minutes, using nothing more than a fingerprint.
Based upon more than 10 years of research, the Intelligent Fingerprinting Drug Screening System uses antibodies to analyze the sweat transferred in a single fingerprint for the presence of cocaine, amphetamines, marijuana, and opiates. Intelligent Fingerprinting founder David Russell, an emeritus professor at UAE, created the platform in the hopes of providing rapid and reliable substance use information on both living and dead subjects, allowing people undergoing testing to submit non-invasive and dignified samples and helping coroners direct their time-sensitive cause-of-death investigations.
And as demonstrated by a recent pilot study published in the Journal of Analytical Toxicology, the innovative method works with accuracies comparable to the gold standard of combined liquid chromatography (LC) and mass spectrometry (MS) of fluid samples.
In real-world experiments set up to test the test, Russell and his colleagues teamed up with three UK coroners to perform fingerprint analysis on 75 randomly selected deceased individuals. The presence or absence of drugs in each person’s system was then confirmed using LC-MS analysis of a second fingerprint sample as well as LC-MS analyses of blood and urine. Using the LC-MS fingerprint results as a measure, the Intelligent Fingerprinting system achieved an accuracy of 98.7 percent for THC, 94.7 percent for cocaine (through the detection of its metabolite BZE), 96 percent for opiates (detection of morphine), and 93.3 percent for amphetamine. The accuracies when compared to traditional blood tests were 96, 92, 88, and 97 percent, respectively.
"This important research demonstrates how there is sufficient sweat present in a subject's fingerprint, regardless of whether the person is alive or dead, to enable our fingertip-based drug screening system to detect the presence of four major drugs of abuse at the same time," co-author Dr Paul Yates said in a statement.
The two-part Intelligent Fingerprinting system – consisting of disposable print-collecting cartridges and a portable cartridge reading machine – identifies pre-specified chemicals with a technique called a fluorescence-based lateral flow competition assay. The part of each cartridge where fingertip sweat is imprinted is a cellulose-based paper strip with four pre-applied stripes of protein-bound versions of each drug compound, plus a fifth stripe of a protein-bound control agent. After a print is applied, the cartridge is loaded into the machine, whereupon fluorescently-tagged antibodies specific to each drug are washed over the drug-protein stripes. A sample with no drug present will show the maximum amount of fluorescence because the antibody will have bound to the drug-protein stripe during the wash.
But if one or more drugs are present in the sweat, the antibodies will preferentially bind to these free drug molecules instead of to the protein-drug complex molecules in the stripe, which leads to a less intense fluorescent signal, as measured by the reader. The print collection phase was found to require about five seconds, while the analysis phase is complete after 10 minutes.
According to the authors, the platform is now in regular use in some coroner’s mortuaries and is being adopted by rehabilitation centers, workplaces, and high schools. Additionally, they revealed that proof-of-concept studies are currently being performed for airport screening and for use within prisons and probation services.