A mean central-to-femoral carbamazepine ratio of 0.97 describes similarity between two postmortem sampling sites in four cases. It does not establish that either concentration stayed unchanged from life to death. The distinction matters because the original authors used the findings to support a stronger statement that carbamazepine was not subject to redistribution.
The carbamazepine denominator was four, not 129
Han and colleagues studied 129 selected drug-related cases investigated by South Korea’s National Forensic Service during 2006–2009. The full study reported 76 drugs, with one to six detected in each case. It did not provide 129 paired results for every compound.
Table 3 gave four carbamazepine cases from the investigators’ own dataset. Their average central/peripheral ratio was 0.97, ranging from 0.74 to 1.16. These were ratios of concentrations, not carbamazepine concentrations in mg/L.
The same table contained results from earlier publications, including animal observations. Those entries must not be pooled silently with the four new human cases or counted as additional independent participants in this study.
What did “cardiac blood” mean here?
Femoral blood was collected after the vein was ligated to reduce drawing blood down from central vessels. The specimen labeled cardiac blood was actually collected from the inferior vena cava after opening the chest and abdomen.
The anatomical description should accompany the label. The data should not be retold as four precisely specified heart-chamber samples, nor automatically transferred to an unrecorded blind-stick collection.
Paired specimens were stored in 50 mL plastic tubes at −20°C. The authors reported approximately three hours from arrival at the facility to collection. That was not the death-to-collection interval, which was unavailable for most cases.
What the ratio supported
The values showed relatively limited site differences in these four observations. They provide drug-specific descriptive context for the sampled compartments. The authors interpreted the result as absence of redistribution and suggested central blood could substitute when peripheral blood was unavailable.
However, a ratio near one can occur even if both sites have changed. There was no antemortem specimen in any case, no serial sampling before autopsy, and no known starting concentration against which either site could be compared. The study therefore could not directly measure each person’s change from life to death.
The range also matters: individual values extended below and above one. Reporting only the mean would hide those differences. Four observations cannot establish universal site interchangeability, particularly across untested intervals, decomposition states or collection procedures.
Analytical performance remained relevant
Carbamazepine was among the drugs quantified by GC–MS. Sample preparation and validation drew on earlier reports and laboratory procedures; the paper did not reproduce a complete carbamazepine-specific numerical validation and uncertainty dataset.
The authors expressly noted that quantification variability should be considered when interpreting site ratios. A small numerical departure from one is not automatically a biological effect, while a precise measurement would not solve the missing antemortem comparison.
The paper’s broad redistribution classifications were descriptive judgments, not results of a carbamazepine-specific statistical equivalence test. There was no demonstrated margin within which two specimens could be treated as equivalent for every forensic purpose.
How the finding should be used
Preserve the four-case denominator, actual collection sites, ligation, storage and missing timing evidence. The result can inform interpretation without supplying a correction factor or proving that an autopsy value equals the concentration during life.
It also cannot determine dose, impairment or cause of death on its own. The separate question of ranking redistribution from volume of distribution in the same study has its own limitations; neither a drug-property ranking nor a near-one site ratio replaces a paired time-course experiment.
Primary source
Han E, Kim E, Hong H, Jeong S, Kim J, In S, Chung H, Lee S. Evaluation of postmortem redistribution phenomena for commonly encountered drugs. Forensic Science International. 2012;219:265–271. doi:10.1016/j.forsciint.2012.01.016.
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