A device for rapid plasma separation.

The STATSEP Plasma Separator (Instrumentation Laboratory, Inc, Lexington, MA), a device for rapidly separating plasma from whole blood, generates plasma at the rate of 0.5 ml/min by filtration rather than centrifugation. When plasma was separated by conventional centrifugation or by the plasma separator, there were no clinically significant differences in concentrations of a variety of important analytes in duplicate specimens. In addition, there were no clinically significant differences in measurements of prothrombin times (PT) and partial thromboplastin times (PTT) on plasmas generated by the 2 techniques. This device, therefore, reduces the analytic time of these frequent coagulation tests by 9 min. The above tests were performed on patients with leukemia and with benign and neoplastic elevations of platelet counts, with no differences seen between plasma specimens separated by either technique. Elevated hematocrits, however, require as much as 2 min to produce 0.5 ml of plasma. Both the machine and disposables are inexpensive and easy to operate.