PB1142 - A rapid centrifugation 4000 g, 4 min does not impact routine coagulation assays.

Background: Centrifugation can represent a choke point when integrated into an automated system offering high throughput testing. Current guidelines from Clinical Laboratory Standards Institute (CLSI) recommends a centrifugation protocol of 1500 g for 15 minutes to achieve low residual platelet plasma ( < 10 G/l).

Aims: The aim of this study was to compare the effect of a rapid centrifugation protocol (4000 g, 4 min) and the standard centrifugation protocol (2500 g, 15 min) on routine coagulation assays.

Methods: Extra blood draws samples from 49 patients from routine testing were selected and centrifuged using either the recommended CLSI protocol of 2500 g, 15 min or the fast centrifugation protocol of 4000 g, 4 min. The experiment has been conducted in two distinct centres (center #1: Clermont-Ferrand; centre #2: Nantes). Coagulation tests (PT, aPTT, fibrinogen, antithrombin, D-dimer, anti-Xa activity, FII, FV, FX, FVII) were performed on STA-R-Max (Stago) using dedicated reagents, except for D-dimer performed on Vidas (Biomérieux). Samples from all centres were pooled for a Bland-Altman analysis and the effect of centrifugation protocols on routine test results were analysed by Student t-test using Graphpad Prism software.

Results: The 4000 g, 4 min centrifugation protocol showed similar results to standard protocol on Bland Altman analysis (mean bias ± SD: PT =-0.02 ± 0.27; aPTT = 0.01 ± 0.03). On most common coagulation tests no significant results were observed and similar means were found: PT (15.20 vs 15.23 seconds), aPTT ratio (1.238 vs 1.242) and fibrinogen (4.23 vs 4.26 g/L). Dosages of antithrombin, D-dimer, anti-Xa activities and extrinsic factors showed no differences between protocols as p-values are comprised in the range of 0.22 – 0.77.

Conclusion(s): The fast centrifugation protocol of 4000g 4 min leads to similar results than the standard protocol, suggesting that the routine centrifugation phase could be shortened to manage samples for coagulation assays.