Overview of Analytical Testing

The data presented in the Drug Checking San Diego (DCSD) dashboard is derived from the high-throughput analysis of trace drug residues and paraphernalia. All samples are processed and analyzed by the National Institute of Standards and Technology (NIST) Rapid Drug Analysis and Research ( RaDAR ) program using Direct Analysis in Real Time Mass Spectrometry (DART-MS) . This approach provides rapid, high-resolution identification of active pharmaceutical ingredients, illicit substances, adulterants, and cutting agents present in the illicit drug supply.

Technical Details and Limitations

While DART-MS is a powerful tool for near-instantaneous screening of complex mixtures, the data must be interpreted with an understanding of the technique's inherent analytical limitations:

• DART-MS represents qualitative analysis only. The dashboard indicates the presence of a compound, but cannot accurately determine the concentration or purity of the substances detected.
• In complex mixtures, detecting trace components may be more difficult. However, potent substances may still be physiologically impactful, or even potentially cause an overdose, at trace quantities.
• DART-MS is also unable to differentiate different enantiomers of the same molecule.
• The sensitivity of DART-MS varies significantly depending on the specific chemical properties of the analyte. Substances with low volatility or poor ionization efficiency may not be detected even if present in the sample.

General Disclaimers

The information presented in this dashboard is intended strictly for public health surveillance, epidemiological research, and harm reduction education. It is not intended for clinical diagnostic use, nor should it be used as a substitute for professional medical advice. A finding of 'No Compounds Detected' or the absence of a specific toxicant does not guarantee that a sample is safe to consume. The illicit drug supply is highly volatile, and testing trace residues represents only a fractional snapshot of a highly heterogeneous market.

About the Project

DCSD is an ongoing public health pilot study (PI: Friedman ), based at the wider cohort study La Frontera (PIs: Strathdee and Skaathun ) and in collaboration with the MI-CHANCE study (PI: Borquez ) at the University of California, San Diego (UCSD). By combining community-engaged harm reduction practices with gold-standard analytical chemistry, the project aims to monitor real-time shifts in the illicit drug supply and provide people who use drugs with actionable, life-saving information.

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