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A Cross-Reactivity of Fenofibric Acid With MDMA DRI Assay
Sarah Bugier1, Carine Garcia-Hejl1, Philippe Vest1
1Laboratory of Biochemistry, Percy French Military Teaching Hospital, 101 Avenue Henri Barbusse, 92140 Clamart, France.
Background:
Within the framework of routine fitness examinations, French Air Force military crew underwent urine testing for 3,4 methylenedioxymetamphetamine (MDMA [ecstasy]). The cross-reactivity of a dyslipidemic drug, fenofibrate, with an MDMA immunoassay was studied and confirmed on a large population sample.
Methods:
A 3-year retrospective study was performed on the MDMA DRI Ecstasy Assay on the Unicel DXC 600. In the event of positive test result, a confirmatory testing was carried out by gas chromatography/mass spectrometry (GC/MS) to establish the presence of MDMA. When analysis by GC/MS did not confirm the presence of MDMA, a false-positive result was suspected and the samples were analyzed by high-performance liquid chromatography-mass spectrometry to identify a potential interfering substance.
Results:
A total of 15,169 urine samples, from 7,803 patients, were tested for 3 years. Of the tested samples, 22 (0.15%) were positive by DRI Ecstasy Assay. None of them were positive by GC/MS. A cross-reactivity of fenofibrate's metabolite with MDMA using this assay was systematically found.
Conclusion:
Fenofibrate's interference with MDMA immunoassay was confirmed. Fenofibrate being widely prescribed, physicians had to be alerted that this treatment could lead to false-positive results.
Insights
Fenofibrate, a common dyslipidemic drug, can cause false-positive results in 3,4-methylenedioxymethamphetamine (MDMA) urine tests. This interference was confirmed in a large study, alerting physicians to potential inaccuracies in drug screening.
Area of Science:
- Clinical Chemistry
- Forensic Toxicology
- Pharmacology
Background:
- Routine fitness examinations for French Air Force personnel include urine testing for 3,4-methylenedioxymethamphetamine (MDMA).
- The potential for cross-reactivity between the dyslipidemic drug fenofibrate and an MDMA immunoassay was investigated.
Purpose of the Study:
- To investigate the cross-reactivity of fenofibrate with an MDMA immunoassay.
- To confirm or refute false-positive results in MDMA screening due to fenofibrate use.
Main Methods:
- A 3-year retrospective study analyzed 15,169 urine samples using the MDMA DRI Ecstasy Assay.
- Positive immunoassay results were confirmed with gas chromatography/mass spectrometry (GC/MS).
- Samples with discrepant results underwent high-performance liquid chromatography-mass spectrometry (HPLC-MS) to identify interfering substances.
Main Results:
- Out of 15,169 samples, 22 tested positive for MDMA by immunoassay, but none were confirmed by GC/MS.
- Systematic cross-reactivity was observed between a fenofibrate metabolite and the MDMA immunoassay.
- HPLC-MS analysis identified fenofibrate's metabolite as the interfering substance.
Conclusions:
- Fenofibrate interference with MDMA immunoassay is confirmed, leading to false-positive results.
- Physicians should be aware that fenofibrate treatment can impact MDMA drug screening accuracy.
- This finding is critical given the widespread prescription of fenofibrate.
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