Tablet residues in gastrointestinal contents? A polarization microscopy screening method for rapid evaluation at the autopsy table

When tablet residues are found in the gastrointestinal tract during autopsy, this does not only indicate the possible presence of intoxication, but may also provide indications with the regard to the kind of intoxication (e.g. suicide) if the amount of tablets is considered. If tablets have already dissolved and thus large portions can no longer be detected with the naked eye, a definitive appraisal with regard to the presence of tablet residues is often difficult or even impossible on the autopsy table. A polarization microscopic screening method is described which enables identification of characteristic tablet auxiliary substances (maize starch, sodium carboxymethyl starch, microcristalline cellulose or sodium carboxymethyl cellulose) to be identified immediately and simply in the gastrointestinal contents. It also enables a rapid orientative screening for tablet residues in glasses found or the fluid these contained as well as in aspirated material and vomit. If the active agent of the tablet can be detected by chemical toxicology, the polarization microscopic diagnosis of abundant tablet auxiliary substances is compatible with intake of large amounts of drugs, which makes self-administration highly probable.