Inclusion Criteria:  This study will be conducted on a group of patients who are diagnosed as COVID-19 by PCR, a group of them have mild symptoms and another group admitted in ICU (critically ill patients).  Exclusion Criteria:  Any clinical condition cause hypercoagulability state such as:  Pregnancy. Recent trauma or surgery. Prolonged bed rest or immobility. Cancer or its medications, such as tamoxifen, bevacizumab, thalidomide and lenalidomide. Hormone replacement therapy. Heparin-induced thrombocytopenia (decreased platelets in the blood due to heparin or low molecular weight heparin preparations). Previous history of deep vein thrombosis or pulmonary embolism. Myeloproliferative disorders such as polycythemia vera or essential thrombocytosis.