Bladder wash as an alternative specimen for postmortem toxicology: Critical evaluation of 87 authentic samples

In post-mortem toxicology, the analysis of various biological matrices is essential for obtaining reliable results. However, conventional matrices may be challenging to analyze using standard protocols or might be unavailable. Bladder washing (BW) has emerged as a valuable alternative when urine samples are absent. This study aims to describe the BW sampling technique and provide a critical evaluation of its current utility in post-mortem toxicological practice.

BW was performed during forensic autopsies, over a three-year period. BW samples were collected from cases where the bladder was empty, using a single 5 mL wash with a 0.9 % NaCl solution. Toxicological analyses were conducted upon request from law enforcement or prosecutors. Screenings for drugs of abuse and medications were performed using LC-MS/MS and LC-HRMS, while volatiles were analyzed by HS-GC-FID. To characterize the wash, creatinine and protein assays were carried out. BW analytical results were subsequently compared to blood analyses in order to determined its sensitivity.

This study included 87 authentic BW samples, with a median BW volume of 2 mL. The subjects, 55.2 % of whom were women, ranged in age from 1 month to 92 years. The median post-mortem interval was 2 days. Sensitivity for drugs and for alcohol and volatiles were 91.6 % and 65.1 %, respectively. No substances were identified in 14 BW samples, mirroring blood findings. Biochemically, 82.2 % of BWs had undetectable creatinine levels (<0.18 mmol/L) and elevated proteinuria (median: 2.92 g/L).

BW yielded satisfactory results as a biological matrix for confirmatory toxicological analysis. Furthermore, this study emphasizes the advantages of close collaboration with forensic pathologists in advancing forensic practice.