The ROtation ThromboElastoMetry analyser (ROTEM, Pentapharm, Munich, Germany) is useful for studying whole blood (WB) clot formation and lysis. Reduction of haematocrit (HCT) has been reported to influence traditional thromboelastography parameters without compromising "in vitro" blood coagulation. We performed this case-control study to evaluate ROTEM profiles in sideropenic anaemia patients with different degrees of reduction of HCT levels. Forty consecutively referred patients with sideropenic anaemia were enrolled. A group of 40 healthy age and gender matched subjects acted as a control. The influence of HCT on ROTEM was assessed in the study population and in a model of artificially reconstituted blood with modified HCT values. Cases presented significantly increased levels of maximum clot firmness (MCF) as compared to controls (p < 0.001) mimicking a sort of "hypercoagulable profile". However, thrombin generation tests failed to detect an increase in thrombin generation in cases as compared to controls. A statistically significant inverse linear correlation between HCT and MCF (p < 0.0001) was found. In addition, ROTEM profiles following "in vitro" manipulation of HCT confirmed the inverse linear correlation between HCT and MCF found in the study population. In conclusion, the increased clot firmness found by ROTEM in anaemic patients is likely to be related to the method in itself rather than representing a marker of hypercoagulability "in vivo". Since ROTEM is widely used by anaesthesiologists when deciding the optimisation of products supplementation during surgery, attention should be paid in the case of anaemic patients taking depending on the peculiar thrombo-elastography profile found.

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Severe factor V (FV) deficiency (parahaemophilia) is a rare congenital hemorrhagic disorder characterized by very low or undetectable plasma FV levels and bleeding phenotype ranging from mild to severe. We evaluated whole blood (WB) rotation thromboelastometry (ROTEM) in parahaemophilia patients and the contribution of intraplatelets FV, if any, to clot formation. Standard ROTEM(®) assays were performed in WB from nine parahaemophilia patients and 50 healthy controls. In addition, platelets poor plasma from one parahaemophilia patient (PPP-Pt) or normal subjects (PPP-N) was reconstituted with washed platelets obtained either from one patient with parahaemophilia (Plts-Pt) or normal subjects (Plts-N) and ROTEM assays were performed in platelets rich plasma (PRP) samples. There was a prolongation of the WB clotting time (CT) in all assays in patients as compared with controls. However, maximum clot firmness (MCF) was similar in patients and controls. ROTEM in PPP-Pt showed both a prolongation of CT and a reduction of MCF as compared with PPP-N. The addition of either Plts-Pt or Plts-N to PPP-Pt resulted in similar increase in MCF and a decrease of CT which was more evident for PPP-Pt + Plts-N than PPP-Pt + Plts-Pt. In contrast, the addition of Plts-Pt or Plts-N to PPP-N had superimposable effects on both CT and MCF. In parahaemophilia patients, WB ROTEM(®) presents mainly with prolongation of CT and no relevant effect on MCF. Residual intraplatelets FV in parahaemophilia contributes significantly to thrombin generation as shown in artificially reconstituted PRP models.

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