Differences between values for plasma and serum in tests performed in the Ektachem 700 XR Analyzer, and evaluation of "plasma separator tubes (PST)".

We measured 25 analytes in plasma and serum from the same blood specimen, using the Kodak Ektachem 700 XR Analyzer. For 22 of the analytes, values for plasma were practically the same as those for serum; for the other three, differences between concentrations in plasma and serum were significant, both statistically and medically. Values for the same analytes in plasma from regular heparinized tubes were essentially indistinguishable from those for plasma obtained by use of Plasma Separator Tubes (PST).