Toxicology Screening

Undifferentiated presentations in the emergency department frequently involve potential drug exposure requiring specialized diagnostic evaluation. Toxicology screening is critical in suspected cases of acute poisoning, overdose, self-harm attempts, or environmental toxin exposure. Substances commonly assessed include therapeutic medications, illicit drugs, and environmental or occupational toxins. Screening relies on methods such as immunoassays for rapid detection and chromatographic or mass spectrometric techniques for confirmatory testing. Indications extend beyond emergency care to forensic investigations, occupational monitoring, and public health surveillance, although this activity emphasizes the acutely ill patient rather than workplace or mandated rehabilitation testing. Interpretation of results is challenged by variability in test availability, detection thresholds, accuracy, and clinical relevance. False positives, false negatives, and narrow detection windows may complicate clinical decision-making. Despite these limitations, toxicology screening informs diagnosis, guides therapeutic interventions, and aids in prognostication for poisoned or overdosed patients. Awareness of the technical constraints, clinical applicability, and potential medicolegal implications of screening is essential for appropriate ordering and interpretation.