by Paul Govern
Urine screening for illicit drug use is widespread in well being care. Utilized by clinicians who prescribe ache drugs, and typically used to information care in emergency departments, these fast and cheap screenings are comprised of assays that take a look at urine for issues like cocaine, opioids, amphetamines, cannabinoids, benzodiazepines (used to deal with anxiousness), barbiturates and sure antidepressants.
Many of those assays, sadly, have excessive false optimistic charges, doubtlessly eroding belief between sufferers and well being care suppliers. The false positives are sometimes resulting from cross-reactivity of those assays with different medication a affected person could also be taking for completely respectable causes. Affirmation testing of optimistic outcomes can rule out false positives, however this definitive testing takes a number of days to finish.
In an award-winning research showing in Scientific Chemistry, Jennifer Colby, PhD, assistant professor of Pathology, Microbiology and Immunology at Vanderbilt College Medical Middle and her husband, Jake Hughey, PhD, assistant professor of Biomedical Informatics and Organic Sciences at VUMC, establish 13 beforehand unknown drug compounds that trigger false optimistic screenings for amphetamines, buprenorphine (an opioid), cannabinoids and methadone.
Drug take a look at producers take a look at for cross-reactivity and embody their findings on the package deal insert, however in keeping with Colby this testing will not be topic to any explicit commonplace of thoroughness.
“Clinicians and scientific labs proceed to discover medication that trigger false positives on these screens and that aren’t famous within the producer’s insert. Even when tutorial findings of this kind make their approach into the laboratory medication literature, they may by no means be famous on the package deal insert,” she stated.
Exploiting VUMC’s strengths in biomedical informatics, Colby and Hughey introduce a brand new technique to type out this difficulty.
It occurs that VUMC’s scientific lab mechanically performs affirmation testing for any optimistic urine drug screens ordered exterior the emergency division. Utilizing deidentified medical file knowledge of sufferers seen at VUMC over a current five-year interval, the investigators assembled a dataset of 40,741 sufferers who underwent urine drug screening. A single VUMC drug screening includes 10 separate assays and within the research’s dataset the false-positive charges for these numerous assays ranged as excessive as 43%.
Within the affected person treatment histories previous these drug screenings, the investigators discovered exposures to some 2,027 completely different energetic drug elements.
They chose for lab validation 13 drug elements related to excessive false optimistic charges of their dataset. They spiked drug-free urine samples with these elements and put the spiked samples by drug screening. All 13 revealed cross-reactivity of urine drug screening and 12 of the 13 produced false positives.
“We’ve proven that utilizing this easy strategy of intersecting lab outcomes and drugs exposures on a big scale you may give you hypotheses for medication which may be inflicting false positives,” Hughey stated.
The investigators additionally recognized a number of drug metabolites that trigger false positives, once more validated utilizing spiked drug-free urine.
As subsequent steps, Colby and Hughey want to information implementation of customized automated scientific resolution help for urine drug screenings as VUMC, in addition to adapt their technique to different scientific lab assays.
The research, which gained an Academy Distinguished Summary Award from the American Affiliation for Scientific Chemistry, was supported partly by the Vanderbilt Information Science Institute and the Vanderbilt Institute for Scientific and Translational Analysis.