On the Comparison of Serum and Plasma Samples in Troponin Assays

With the emphasis on rapid turnaround time as a crucial predicate requirement for cardiac marker measurements, the use of plasma instead of serum samples is desirable because use of plasma eliminates the need for sample clotting (1). Dorizzi et al. (2) have discussed in a recent letter possible problems associated with the use of various types of samples in different generations of the Dade Behring Dimension RxL assay for cardiac troponin I (cTnI). Their main message, useful for the Journal’s readers, is that both serum and heparin-plasma samples are suitable for cTnI determinations in the first and second generations of the assay. In our opinion, their presentation and interpretation of their results are questionable. The figure presented by Dorizzi et al. (2) contains some conceptual and graphical errors. Because serum is the matrix …