A visually distinctive residue is not automatically a validated forensic identification.
The laboratory study included clonazepam among several medicinal products. It examined dried-droplet patterns with optical and texture analysis after deliberate dilution or added substances. Detection depended on comparison with an unaltered sample and controlled preparation conditions.
The authors noted limited sensitivity to lower dilution levels and dependence on substrate, humidity, volume and temperature. The work did not validate authentic blood or urine testing or establish chemical specificity for every possible contaminant. Reported classification accuracy applies to the tested setup.
For an analytical opinion, identify the sample type, control preparation and error evaluation. Do not transfer a medicine-quality-control classifier to impairment or drug identity in an unrelated biological specimen. Pattern recognition can flag differences without independently proving their chemical cause or clinical meaning.
Source: Publication PMC8231125. Applications to expert review are interpretive analysis.
Related reading: Lorazepam NMS Review Drew From Case Reports Rather Than Controlled Trials.