Evaluation of a new system ("Corvac") for separating serum from blood for routine laboratory procedures

We evaluated the suitability of a new system ("Corvac," Corning) for rapid, complete separation of cell-free serum from whole blood. Twenty-one different clinical chemical procedures were performed on about 1150 paired blood samples, several by more than one method, to afford a more comprehensive evaluation. The tube of clotted blood collected in the conventional manner ("Vacutainer") underwent a double centrifugation and served as the control sample, while its paired specimen collected in the new system was processed by a single centrifugation. We evaluated significant differences between the means of the paired samples, the standard deviations of the differences between the means, and the bias of the means for the values of each constituent for each collection method. For several tests we observed differences that were statistically but not clinically significant. Only in the case of lactate dehydrogenase were large differences consistently demonstrated.