Evaluation of a 4 min 4000g centrifugation protocol for routine coagulation assays.

Centrifugation is a critical step in sample preparation and accounts for an important part of turnaround time. This step is further critical for hemostasis, which requires a low platelet count to produce reliable results. For automated laboratories, centrifugation can represent a bottleneck and thus a shorter centrifugation time would benefit tube flow and turnaround time. We compared a rapid centrifugation protocol (4000g 4 min) with the recommended protocol (2200g 15 min) at two different centers, after one or two centrifugation cycles. The effect of each protocol was assessed on the platelet count at every step to verify the capacity of the protocol to yield platelet-poor plasma (PPP). Results on 16 coagulation parameters were compared to verify the reliability of rapid centrifugation. In one center, a consecutive two-cycle centrifugation had been tested on platelet count. A single centrifugation cycle, using the rapid protocol, produced plasma with increased residual platelets compared with the GEHT (Groupe Etude sur l'Hémostase et la Thrombose) protocol. Despite this difference, the coagulation results were interchangeable between the protocols. In addition, a second centrifugation cycle produces plasma with a mean residual platelet less than or equal to 10 × 109/l. A single cycle of rapid centrifugation can be used to assess prothrombin time (PT), activated partial thromboplastin time (aPTT), aPTT kaolin, thrombin time (TT), fibrinogen, antithrombin (AT), D-dimers, anti-Xa, factor II (FII), factor V (FV), factor VII (FVII), and factor X (FX). For frozen plasmas, a double-cycle followed by a third cycle should be performed to ensure that 100% of samples contain less than 10 × 109/l platelets.