Failure to find a statistically significant decomposition-group difference did not establish that advanced putrefaction leaves drug concentrations unchanged. A Dutch autopsy study’s null comparisons must be read alongside its small advanced-decomposition groups and its use of postmortem site ratios rather than predeath measurements.
What population was actually studied?
de Groot and colleagues reviewed Netherlands Forensic Institute investigations from January 2010 through July 2020. Inclusion required a studied amphetamine-group drug or benzodiazepine to be quantified in both femoral and central blood. The datasets contained 112 amphetamine-group cases and 179 benzodiazepine-positive cases; individual compounds had different paired denominators.
Cases therefore needed sufficient material and quantitative results at both sites. The findings did not validate testing when decomposition left no usable blood. Nor did the investigators follow the same bodies prospectively through successive stages of decay.
Most stimulant observations were in early grades
For amphetamine, Table 5 listed 47 cases in decomposition grade I and 20 in grade II. There were only two in grade III, three in grade IV and two in grade VI. The overall decomposition comparison had p = 0.245.
MDMA had 26 grade-I and 11 grade-II cases, with one grade-V case. MDA had 22 grade-I and 11 grade-II cases, with one grade-VI case. Their decomposition comparisons had p = 0.242 and p = 0.135, respectively. These available graded observations did not exhaust every analyte’s full paired dataset.
None of those comparisons met the study’s corrected amphetamine-group significance threshold of p < 0.0045. A single advanced-grade observation, however, cannot characterize the range expected in that grade or demonstrate equivalence with early decomposition.
The benzodiazepine comparisons had similar coverage limits
Midazolam had 45 grade-I, 11 grade-II and two grade-III cases, with p = 0.072 for the decomposition comparison. Its metabolite α-hydroxymidazolam had 23, seven and one, respectively, with p = 0.884. The study reported no significant decomposition-group differences for the investigated benzodiazepines.
The authors specifically noted that decomposition was mostly limited to grades I and II and considered that limited range a possible explanation for the absent differences. They also acknowledged small subgroup sizes as a general limitation despite reviewing more than ten years of casework.
A stable ratio would not prove stable concentrations
The measured endpoint was central concentration divided by femoral concentration. Both concentrations could change without producing a comparable change in their ratio. No paired antemortem specimen established stability relative to life, and no controlled serial collection separated degradation from redistribution or fluid mixing.
The null statistical result therefore cannot support a claim that putrefaction is irrelevant, that either blood site preserved the original concentration, or that every drug behaves similarly.
Collection and laboratory handling were specified
Femoral blood was obtained after targeted dissection before internal examination. Central samples came from the right atrium or inferior vena cava with the heart in situ. Glass tubes contained sodium fluoride and sodium heparin; samples were frozen at −20°C and analyzed within three months after collection.
Screening was followed by quantitative UPLC–MS/MS. Those procedures establish how collected material was investigated. They do not reverse changes that occurred in the body before collection, and the study supplied no decomposition-specific correction formula.
How should the null result be used?
Retain the decomposition grade, subgroup count, analyte, collection site and statistical threshold. Distinguish failure to detect a difference from evidence that a clinically or forensically meaningful difference is absent. Neither the ratio nor drug detection alone establishes dose, impairment or cause of death.
The separate problem of unavailable specimens is illustrated by diphenhydramine cases in which decomposition left no blood for testing.
Primary source
de Groot ADE, Borra LCP, van der Hulst R, et al. Postmortem redistribution of amphetamines and benzodiazepines in humans: Important variables that might be influencing the central blood / peripheral blood ratio. Forensic Science International. 2023;353:111876. doi:10.1016/j.forsciint.2023.111876.
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