Blood collection technique: no effect on in vitro protein binding of prednisolone.

The effect of the blood collection vessel and systemic heparin administration on in vitro protein binding of prednisolone was examined in blood collected from human subjects. No differences in the fractional binding of prednisolone were found in plasma from plain glass culture tubes, heparinized culture tubes, and two types of red- and green-top commercial vacuum tubes. Thus, these blood collection techniques do not alter serum or plasma albumin and transcortin binding of prednisolone.