Comparing ELISA and LC-MS-MS: A Simple, Targeted Postmortem Blood Screen.

Area of Science:

• Forensic Toxicology
• Analytical Chemistry
• Mass Spectrometry

Background:

• Immunoassays are common in forensic toxicology for drug screening due to cost-effectiveness and sensitivity.
• Increasing accessibility of mass spectrometry necessitates re-evaluation of screening methods.
• A need exists for specific, accurate, and customizable screening methods in forensic labs.

Purpose of the Study:

• To develop and validate a comprehensive screening method for 42 drugs in postmortem blood.
• To compare the performance of a novel LC-MS-MS method against traditional ELISA.
• To assess the method's suitability for forensic laboratories within budget constraints.

Main Methods:

• Developed and validated a drug screening method for postmortem blood using liquid chromatography-tandem mass spectrometry (LC-MS-MS).
• Employed minimal sample preparation involving only protein precipitation.
• Validated the method according to Organization of Scientific Area Committees for Forensic Science guidelines, including LOD, interference, stability, and ion suppression studies.
• Analyzed over 100 case samples comparing LC-MS-MS to ELISA.

Main Results:

• The LC-MS-MS method demonstrated comparable or superior performance to ELISA in nearly all analyzed cases.
• The method requires minimal sample preparation and uses only two internal standards, reducing costs.
• Limit of detection, interference, stability, and ion suppression were thoroughly examined.

Conclusions:

• The developed LC-MS-MS method is a reliable, accurate, and cost-effective alternative for drug screening in forensic toxicology.
• This method offers improved specificity and the flexibility to add more drug targets.
• It is ideal for forensic laboratories seeking enhanced screening capabilities while managing costs.