Laboratory tests
VIRUS, HEPARIN INDUCED THROMBOCYTOPENIA
After reaching the steady state (usually after the third dose), heparin levels were measured with the determination of anti-Xa activity on a blood sample obtained at 4 h after the morning injection. LMWH dose could then be increased or reduced according anti-FXa (anti-Xa) activity (0.4–0.6 anti-Xa UI/ml for intermediate doses) [The determination of anti-Xa activity was repeated on the fifth or sixth day to monitor any drug accumulation. anti-Xa activity was measured according to locally available test. The effective doses of study drugs received by each participant during the study were recorded.Complete blood cell count was obtained every second day to monitor for heparin induced thrombocytopenia.D-dimer values were determined locally, and values were expressed as ng/ml in FEU (Fibrinogen Equivalent Units) and those measurements expressed as D-Dimer unit were converted into FEU. D-dimer values were expressed as a ratio of the upper limit of reference value (x ULN). In all patients, RT-PCR nasopharyngeal swabs were performed every 7 days to assess virus clearance and determined locally. All other laboratory tests were determined locally.