Femoral blood is not guaranteed to preserve the concentration present at death after a long postmortem interval. In one extensively sampled autopsy, methamphetamine ranged from 268 to 911 ng/mL across nine blood locations after an estimated six to seven days. The authors proposed loss through venous walls as an explanation for part of the pattern, but the study did not directly measure that movement or establish the concentration during life.
The case and collection conditions
Wurita and colleagues investigated a 71-year-old man found dead in his apartment. His history included diabetes, chronic renal failure, hypertension, hepatitis and coronary disease. The body was kept in a refrigerated morgue at 2–4°C for six days before autopsy. Myocardial infarction was considered the direct cause of death, with methamphetamine discussed as a possible contributing influence rather than an independently established sole cause.
The investigators obtained 21 specimens: blood from nine cardiac or vascular locations, pericardial fluid, bile, stomach contents and nine solid tissues. No urine was available. Specimens were stored at −80°C until analysis. The estimated total postmortem interval and the period of refrigerated storage should not be confused with an experiment conducted continuously at ambient temperature.
The blood measurements
The right femoral venous result was 268 ±14.9 ng/mL, while left heart blood measured 911 ±46.2 ng/mL. Right heart blood measured 589 ±14.6 ng/mL. These are reported means and standard deviations from triplicate analytical determinations of specimens from one person, not variation across multiple deaths.
The pulmonary vein result, 567 ng/mL, was below left heart blood. Superior and inferior vena cava results were 566 and 415 ng/mL, and right iliac venous blood measured 409 ng/mL. Aortic arch and pulmonary arterial blood measured 733 and 805 ng/mL respectively. Simply labeling all of these specimens “central blood” would conceal material differences.
Amphetamine was also quantified as a methamphetamine metabolite. Its right femoral result was 7.28 ng/mL. Co-detection did not convert the case into a controlled exposure experiment with a known dose or administration time.
What the proposed diffusion mechanism means
The authors suggested that diffusion through relatively thin venous walls could reduce drug concentrations during a prolonged postmortem interval, while thicker arterial walls might retain drug differently. They also discussed contributions from organs and tissues.
These were interpretations of a distribution snapshot. There was no antemortem specimen, serial blood collection or direct measurement of passage through a vessel wall. A low femoral concentration relative to another site does not prove how much drug was lost. Nor does the highest measured blood result become a validated estimate of the concentration at death.
The authors suggested considering femoral skeletal muscle in this setting, but the single case did not validate a muscle-to-blood conversion. Tissue concentrations and blood concentrations must retain their respective ng/g and ng/mL units.
How the laboratory measurements were supported
Screening first identified amphetamines in pericardial fluid by immunoassay and methamphetamine in blood by GC–MS. Subsequent quantitation used liquid chromatography–tandem mass spectrometry with deuterated internal standards, modified QuEChERS extraction and specimen-specific standard addition.
Reported detection and quantitation limits were approximately 0.5 and 1.0 ng/mL or ng/g respectively. Calibration correlations exceeded 0.99. Repeatability assessed in femoral blood, liver and stomach contents had relative standard deviations no greater than 10.8%. Matrix response in those examples ranged from 58.8% to 95.2%, and recovery ranged from 66.1% to 109%.
The authors did not supply conventional accuracy and precision validation for every matrix, instead presenting repeated determinations in selected specimens. Good analytical repeatability does not resolve the separate uncertainty about biological change before collection.
The practical interpretive limit
The study supports recording the exact vessel or cardiac compartment and the collection timeline. It does not supply a universal correction, an impairment threshold or a fatal concentration. For related distinctions, see what specimen ratios can establish and analytical identification versus postmortem interpretation.
Primary source
Wurita A, Hasegawa K, Minakata K, et al. Postmortem redistribution of methamphetamine and amphetamine in blood specimens from various blood vessels and in the specimens from pericardial fluid, bile, stomach contents and various solid tissues collected from a human cadaver. Forensic Toxicology. 2016;34:191–198. https://doi.org/10.1007/s11419-015-0303-8.
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