Three paired methamphetamine cases documented higher postmortem peripheral blood concentrations than earlier whole-blood concentrations. Their reported mean ratio of 1.51 was a summary of those three observations, not a validated factor for reconstructing every person’s concentration during life.
Both specimen type and anatomical site matter
McIntyre and colleagues examined three San Diego medical-examiner cases with antemortem whole blood available. Those samples were collected seven to 22 minutes before death was pronounced. The anatomical sites of the earlier clinical collections were not specified.
Postmortem peripheral samples came from the iliac arteries in the pelvis, not the femoral veins. They were collected at autopsy and stored in 10 mL glass tubes containing 100 mg sodium fluoride and 20 mg potassium oxalate. Samples were refrigerated at 4°C before and after analysis.
These were within-person comparisons of earlier and later whole blood. They were different from comparing unrelated living patients with an autopsy population, and different from comparing two simultaneous postmortem blood sites.
The actual pairs showed the scale of change
| Case | Antemortem blood | Postmortem iliac blood | Reported postmortem/antemortem ratio |
|---|---|---|---|
| 1 | 0.19 | 0.34 | 1.79 |
| 2 | 0.33 | 0.44 | 1.33 |
| 3 | 9.3 | 13.0 | 1.40 |
The reported mean methamphetamine ratio was 1.51. Amphetamine was not detected in case 1. In cases 2 and 3, amphetamine increased from 0.05 to 0.07 mg/L and from 0.10 to 0.16 mg/L, giving ratios of 1.40 and 1.60 and a mean of 1.50 across two pairs. The metabolite mean did not have three quantitative pairs.
The intervals and causes of death differed
Case 1 involved a 44-year-old man with hypertensive and atherosclerotic cardiovascular disease, with methamphetamine intoxication listed as contributing. Earlier blood was collected 22 minutes before pronouncement; autopsy occurred 30.5 hours after death.
Case 2 involved a 46-year-old man who died from multiple blunt-force injuries after a rollover crash. Earlier blood was collected seven minutes before pronouncement and autopsy occurred 22.5 hours after death. Cannabinoids were identified but not quantified.
Case 3 involved a 37-year-old man whose death was attributed to acute methamphetamine intoxication. Earlier blood was collected nine minutes before pronouncement; autopsy occurred 5.25 hours after death. Gastric findings supported recent ingestion, creating uncertainty about complete absorption and distribution. All three underwent resuscitative efforts.
The longest interval coincided with the largest ratio, but three heterogeneous cases did not establish an hourly rate or prove that elapsed time caused that ordering.
Screening preceded confirmation and quantitation
Antemortem specimens underwent drug screening by ELISA and alcohol testing by headspace GC-FID. Methamphetamine and amphetamine in both earlier and postmortem specimens were confirmed and quantified by GC–MS after solid-phase extraction and derivatization, with deuterated internal standards.
The reported calibration interval was 0.02–2.0 mg/L, detection limit 0.01 mg/L and quantification limit 0.02 mg/L. Over 42 determinations, accuracy at 0.10 and 0.40 mg/L was 103% and 109% for methamphetamine and 100% and 105% for amphetamine; corresponding CVs were 2.9% and 3.7%, and 3.0% and 2.6%.
Case 3’s reported concentrations exceeded the stated calibration interval. The paper did not describe the case-specific dilution or extended calibration needed to evaluate those high results. That reporting limitation should remain visible rather than being filled with an assumed procedure.
What conclusion is supported?
The authors interpreted the paired increases as evidence of postmortem redistribution. The observations support caution even with peripheral blood. They do not provide a population prediction interval, universal correction, dose estimate or impairment threshold. A sample shortly before pronouncement is also not necessarily the exact concentration at the moment circulation stopped.
Preserve each original concentration and collection time. Dividing a new postmortem result by 1.5 would substitute a three-case average for an unmeasured individual history. For a separate comparison, see amphetamine concentration groups and cardiac/femoral ratios.
Primary source
McIntyre IM, Nelson CL, Schaber B, Hamm CE. Antemortem and Postmortem Methamphetamine Blood Concentrations: Three Case Reports. Journal of Analytical Toxicology. 2013;37:386–389. doi:10.1093/jat/bkt040.
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