Table 2 Toxicological screening

Rapid screening methods on an automated chemistry analyzer

Immunological and enzymatic

Urine screens for illicit drugs and/or their metabolites (cocaine, amphetamines, opiates, etc.) without assay

Useful for “conventional” drugs, excluding NPS

These tests need to be carefully interpreted (molecule identified by antibody, toxicokinetics, screening window, interferences, etc.)

Limits of interpretation on urine

Specific drug or toxin screens with blood and/or urine assays

Useful for blood assays (drugs, ethanol, etc.)

Limits of interpretation on urine

Drug class screens (benzodiazepines, tricyclic antidepressants, etc.) in blood and/or urine

Limits of interpretation for a drug of the class identified by antibody due to cross-reactions with other drugs of the same class and possible interferences

Need for biological interpretation with respect to the toxicity thresholds of each drug

Limits of interpretation for urine

Chromatographic confirmation of screening methods

Liquid or gas chromatography

Detection by diode arrays and/or mass spectrometry in blood and/or urine

Useful for broader targeted screening (up to 1200 molecules and/or metabolites)

Need for biological interpretation of the nature of the molecules identified, the level of screening (sensitivity) and interpretation with respect to reported toxic concentrations

A semiquantitative approach can be used simultaneously with screening for certain molecules

Limits of interpretation on urine

Liquid chromatography

High-resolution mass spectrometry (HRMS)

Useful to identify unknown chemical structures (non-targeted screening) (e.g. NPS)