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Detecting Drug Exposure Long After the Fact: New Method Proves Effective

NCJ Number
Date Published
October 2023

This article addresses the challenge posed by detecting drug-use after the fact, or retrospective drug monitoring, and reports on the development of a new blood protein modification assay that researchers suggest will benefit criminal justice research.


Drug abuse and involuntary drug exposure have far-reaching consequences for individuals, families, and communities. Investigators often need forensic toxicologists to provide evidence of an individual's history of drug use or exposure, even if it dates further back than commonly used tests can determine. Such testing can detect drug-facilitated sexual assault, compliance with probation and parole, or compliance with addiction rehabilitation programs. When a human body breaks down a drug, it forms drug metabolites that can be analyzed in blood or urine, among other samples. Forensic toxicologists assess drug use and drug exposure by looking for the presence of these metabolites and measuring them. However, the body tends to clear drug metabolites within one week, and often sooner. Therefore, detecting drug use after the fact presents a challenge. To increase the window of time that a drug exposure can be detected, researchers supported by the National Institute of Justice have created an innovative, sensitive, and specific method to detect drug exposure which is fundamentally different than traditional toxicological drug testing.

Date Published: October 1, 2023