Clinical Scorecard: Last Orders for Drug Residues?

At a Glance

Key Highlights

• Researchers collected 420 swabs over three weeks; confirmatory LC-MS detected cocaine and ketamine, with 320 positive detections.
• Direct, untargeted ASAP-MS mainly detected samples with relatively high cocaine levels and missed many lower-level residues.
• Methanol extraction with targeted ASAP-MS increased sensitivity versus direct untargeted analysis, but false-negative rates remained high.
• Across ASAP-MS workflows, researchers recorded 15 false-positive results; procaine contributed to some apparent ketamine signals.
• Surface residues indicate presence on a surface but do not establish consumption, timing, route of deposition, or responsibility.

Guideline-Based Recommendations

Diagnosis

• Use LC-MS as the laboratory comparator for confirming residues in this study; ASAP-MS results alone were not reliable for confirming presence or absence.
• Interpret apparent ketamine signals cautiously because procaine can produce a similar mass signal on a single-quadrupole instrument without chromatographic separation.

Management

• The study supports considering ASAP-MS as an initial screening approach rather than a confirmatory method.
• Methanol extraction combined with targeted ASAP-MS acquisition improved trace detection compared with direct untargeted analysis.

Monitoring & Follow-up

• Further method development should address temperature control, extraction volumes, matrix-matched controls, and data-analysis software before routine on-site screening.

Risks

• Targeted extraction ASAP-MS missed 59.51% of LC-MS cocaine-positive samples and 88.57% of LC-MS ketamine-positive samples.
• Surface residue findings cannot determine whether a drug was consumed at the venue or when, how, or by whom it was deposited.

Patient & Prescribing Data

Not applicable; the study analyzed environmental surface swabs rather than patients.

No prescribing or treatment data were reported.

Clinical Best Practices

• Distinguish environmental residue detection from evidence of consumption or individual drug use.
• Treat ASAP-MS as a screening method in this study, not as a definitive test for presence or absence.
• Consider the reported false negatives and potential compound interference when interpreting ASAP-MS findings.

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