Bupropion interference with immunoassays for amphetamines and LSD

Area of Science:

• Clinical Toxicology
• Forensic Chemistry
• Pharmacology

Background:

• Drug screening assays are crucial for diagnosing intoxication and in forensic investigations.
• Immunochemical assays, like Cloned Enzyme Donor Immunoassay (CEDIA), are widely used for initial drug screening due to their speed and cost-effectiveness.
• However, these immunoassays can be susceptible to interference from various compounds, leading to false-positive or false-negative results.

Observation:

• A previously healthy 50-year-old male presented with sudden loss of consciousness and seizures.
• Initial urine drug screening using Cloned Enzyme Donor Immunoassay (CEDIA) yielded positive results for amphetamines and Lysergic acid diethylamide (LSD).
• These initial findings could not be confirmed by more specific analytical methods.

Findings:

• Advanced toxicological analysis employing Gas Chromatography/Mass Spectrometry (GC/MS) and Liquid Chromatography/Mass Spectrometry (LC/MS) was performed.
• Bupropion, a prescription medication used for smoking cessation, was identified as the interfering substance in the patient's urine sample.
• Bupropion was determined to be the cause of the false-positive immunoassay results for amphetamines and LSD.

Implications:

• This case highlights the potential for bupropion to interfere with CEDIA drug screening assays, leading to inaccurate initial results.
• Clinicians and toxicologists must be aware of potential drug interferences in immunoassay testing to avoid misdiagnosis and inappropriate treatment.
• Confirmatory testing using mass spectrometry-based methods (GC/MS, LC/MS) is essential when initial screening results are unexpected or inconsistent with the clinical presentation.