Screening postmortem whole blood for oxycodone by ELISA response ratios

Area of Science:

• Forensic Toxicology
• Analytical Chemistry
• Immunoassay Development

Background:

• Accurate detection of oxycodone in postmortem samples is crucial for forensic investigations.
• Immunoassays offer a rapid screening method, but their specificity in complex biological matrices like postmortem blood requires validation.

Purpose of the Study:

• To assess the accuracy of a screening method for postmortem whole blood oxycodone detection.
• To determine the utility of an oxycodone immunoassay response ratio compared to a general opiate immunoassay response.

Main Methods:

• Analyzed 58 opiate-negative and 158 opiate-positive postmortem whole blood specimens.
• Used Neogen Oxymorphone/Oxycodone ELISA and Neogen Opiate Group ELISA to calculate an Oxycodone/Opiates Response Ratio.
• Compared ELISA ratio results with Gas Chromatography-Mass Spectrometry (GC/MS) data.

Main Results:

• Receiver Operating Characteristic (ROC) analysis identified an optimal response ratio cutoff of 2.0.
• At a cutoff of 2.0, the ELISA response ratio demonstrated 89.4% sensitivity and 88.1% specificity for oxycodone detection.
• A ratio of 2.0 or higher indicated a >50% probability of oxycodone presence in populations with >15% prevalence.

Conclusions:

• The developed immunoassay ratio method provides an accurate and efficient screening tool for oxycodone in postmortem whole blood.
• This method can aid forensic laboratories in prioritizing samples for confirmatory testing, improving workflow efficiency.
• The validated screening approach contributes to reliable postmortem drug analysis and interpretation.