• Jens Holtappels, Robert Zimmermann, and Geoffrey Lee.
• Clin Lab. 2018 Jan 1; 64 (1): 185-192.

BackgroundThe use of colloidal silica contained in different cryopellet formulations is examined as a contact activator of blood in an intrinsic coagulation test. In particular the necessary amount of silica per cryopellet was determined, as well as the interfering effects of cryopellet components on coagulation.MethodsCryopellets were prepared using an established technique and were tested by rotational thromboelastometry using recalcified whole blood. The clotting time (CT) and maximum clot firmness (MCF) were determined from the dynamic coagulation profiles.ResultsLevels of silica of 25 - 75 µg per cryopellet weight of 1.25 mg reduced CT to below 200 seconds and gave good MCF. Trehalose had no effects of coagulation, whereas mannitol reduced CT by a third. The incorporation of silica in the liquid feed used for cryopelletization did not inhibit uniformity of droplet and hence cryopellet weight. The activating activity of the silica [CT and MCF] was the same as that of a classic intrinsic assay using ellagic acid.ConclusionsA silica-containing cryopellet can be prepared and works as well as ellagic acid as an activator in intrinsic rotational thromboelastometry. A cryopellet avoids dilution of the whole blood sample and hence also of coagulation-relevant blood components that can alter the coagulation result.

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