A poisoning study supports caution about negative urine screens, but one reported count must be reconciled before quoting its detection percentage.
The retrospective study included 501 suspected acute-poisoning patients with negative immunochromatographic urine results and examined blood by mass spectrometry. Benzodiazepines were prominent findings. The abstract reported 239 patients for one detection category, while the body reported 293, with a 58.8% figure appearing in the reporting.
The discrepancy prevents accepting a single prevalence figure without clarification of count and denominator. Urine and blood are different matrices, and the study did not measure urine concentrations to directly resolve cutoff-related negatives. Selected poisoning cases do not establish screening sensitivity in every tested population.
A forensic report should preserve the robust qualitative point while flagging uncertain numbers: a negative screen does not exclude relevant exposure. Do not silently choose the more favorable count. Assay targets, metabolites, cutoff, matrix, and collection timing must be examined for the individual result.
Source reviewed: Evaluation of immunochromatography based urine drug screening and blood drug concentrations in suspe (PMC12888314). Forensic applications above are interpretive analysis of the supplied paper.
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