Impact of Centrifuge Braking on Platelet-Poor Plasma for Hemostasis Testing.

Background: Preanalytical conditions, particularly centrifugation protocols, are critical for producing high-quality platelet-poor plasma in hemostasis testing. Centrifuge braking is debated due to its potential impact on platelet remixing.

Objectives: To evaluate the effect of centrifuge braking on residual platelet counts and a broad panel of hemostasis assays using both fresh and double-centrifuged plasma.

Methods: Fifty-six adult patients provided surplus citrate plasma samples. Three centrifugation protocols were assessed: 2000 g for 15 min with braking (B+/2000/15), 2500 g for 10 min with braking (B+/2500/10), and 2500 g for 10 min without braking (B-/2500/10). Routine assays were performed on fresh plasma. Specialized assays (factors VIII, IX, XI, XII, VWF, protein C, protein S, antithrombin, APC resistance, DRVVT, antiphospholipid antibodies) were performed on frozen plasma after double-centrifugation. Platelet counts and assay concordance were evaluated.

Results: Residual platelet counts were significantly higher in the B+/2500/10 protocol (9 [6-13] × 10/L) compared to B-/2500/10 (2 [2-4] × 10/L, p < 0.001) and B+/2000/15 (3 [2-4] ×10/L, p < 0.01). All frozen samples had platelet counts < 10 × 10/L. Routine coagulation assays were unaffected by protocol choice, except for a slight but statistically significant increase in factor V with braking. Specialized assays showed no meaningful differences across protocols, with the exception of a minor DRVVT confirmation time reduction in the braking group.

Conclusion: Braking during centrifugation reduces processing time but modestly increases residual platelet counts. Nonetheless, it does not compromise the performance of hemostasis assays when protocols are appropriately validated. These findings support the use of braking in clinical laboratories.