Histological paraffin-embedded block: a good alternative specimen to detect the use of opiates at least 20 years ago.

Purpose: Since the solely certain remnants of a performed autopsy are formalin-fixed paraffin-embedded (FFPE) samples, stored in the archives of every institute of legal medicine, we managed to extract molecules of toxicological interest from these specimens.

Methods: We assessed the analysis of ten fresh liver samples collected from heroin-related deaths and then histologically processed the same samples. The embedded blocks were then extracted by means of a new extracting method and the eluates were measured. We also selected five toxicological cases of heroin-related fatalities that were examined 20 years ago, collected the toxicological result documents of the analysis that were carried out at the time and then processed the corresponding FFPE liver samples that were stored in the archives.

Results: We managed to isolate heroine-related metabolites from 20-year-old paraffin-embedded blocks and calculated ratios to evaluate the performance of our new extraction.

Conclusions: According to our study, it is feasible to carry out a toxicological examination on old histological samples and, therefore, this matrix can be considered as a new alternative specimen for chemical-analytical evaluations of past cases or when fresh samples are not available anymore. The new extractive method was evaluated as efficient in treating these complex, paraffin-embedded samples. It was surprising that the target compounds could be quantitated from FFPE bocks created as long as 20 years ago.