CEDIA dau Benzodiazepine screening assay: a reformulation

Area of Science:

• Clinical Chemistry
• Forensic Toxicology
• Immunoassay Development

Background:

• Benzodiazepine glucuronide conjugates are major urinary metabolites.
• Accurate detection of low-dose benzodiazepines is challenging due to low metabolite concentrations.
• Existing immunoassays may require hydrolysis for optimal sensitivity.

Purpose of the Study:

• To evaluate a reformulated CEDIA dau Benzodiazepine assay with online hydrolysis.
• To assess the assay's performance for detecting urinary benzodiazepine glucuronides.
• To compare online hydrolysis with offline hydrolysis and no hydrolysis.

Main Methods:

• Reformulation of the CEDIA dau Benzodiazepine assay to include online hydrolysis.
• Evaluation using lorazepam as a probe drug in human urine samples.
• Comparison of E. coli beta-glucuronidase (online) with Helix pomatia beta-glucuronidase (offline) hydrolysis.
• Assay performance assessed using a nitrazepam calibration cutoff.

Main Results:

• The reformulated assay detected benzodiazepines in urine samples for 5-24 h to 2-35 h post-dose.
• Online hydrolysis with E. coli beta-glucuronidase showed no significant difference from offline hydrolysis.
• Urine samples tested negative without hydrolysis, highlighting the necessity of the hydrolysis step.
• Lorazepam glucuronide showed significant cross-reactivity with online hydrolysis (72-136%).

Conclusions:

• The reformulated CEDIA dau Benzodiazepine assay with online hydrolysis is effective for detecting urinary benzodiazepine glucuronides.
• The assay demonstrates enhanced sensitivity for low-dose benzodiazepines.
• Online hydrolysis provides a practical and effective method for improving benzodiazepine detection in urine drug screening.