The Milan autopsy series reported mean cocaine concentrations of 5.37 µg/mL in cardiac blood and 5.28 µg/mL in femoral blood in a category of 15 acute single-substance intoxication deaths. Table 1 rounded the ratio of those two means to 1.0. Its footnotes show that the cardiac mean used 13 cases and the femoral mean used 14. The two means therefore did not summarize identical sets of specimens.
A rounded ratio close to one can be useful as a description of that table. To assess agreement within decedents, however, the relevant observations are the paired cardiac and femoral results from each decedent with both specimens available. Dividing two averages cannot show the distribution of the individual ratios, the effect of an extreme result, or the extent of disagreement in a particular case.
Identify the sampling site for each result, which decedents contributed to each summary and how missing specimens were handled. When an opinion relies on a published cardiac-to-femoral ratio, ask whether it comes from matched pairs, how variable those pairs were and why that comparison would apply to the substance and specimen at issue.