Variability amongst urine toxicology amphetamine readings with concurrent administration of fenofibrate

Abstract

It is evident that different pathology laboratories may utilise different commercial urine drug-screen immunoassays in their toxicology analysis, with variability in the test specificities. Despite the relatively high prevalence of substance misuse in the population of psychiatric inpatients, there exists a need for increased vigilance towards the possibility of false-positive amphetamine results owing to likely cross-reactivity of fenofibrate with the test reagents. In cases where there is uncertainty when correlating clinically, or where false positives are suspected, gold-standard urine-sample analysis by mass spectrometry should be considered, particularly when the consequences for patients may include restrictive measures.

Patients in medical treatment for attention deficit/hyperactivity disorder (ADHD): Are they at risk in drug screening?

“…'False positive' drug screening results for amphetamine have also been associated with use of other drugs and herbal foods (Baron et al 2011;Dadlani et al 2018;Liu et al 2015;Marin et al 2016;Olsen et al 1992;Papa et al 1997;Pavletic and Pao 2014;Vorce et al 2011). This also includes case reports for common drugs, e.g.…”

The multiple facets of addiction in psychiatry

“…Of course, prior work in this journal has suggested that in many common clinical situations UDS adds little to good history taking and interview skills 6 , but now in this issue we are given further evidence that results need to be interpreted with caution. Dadlani et al 7 highlight the risk that a common lipid-lowering drug can variably cause false positive UDS for amphetamines, depending on the specific assay used by the laboratory. This may be especially problematic for managing outpatients whose UDS may be undertaken by different laboratories on different occasions.…”