Abstract: Although the approval of more than one vaccine, the continuity of high incidence establishes the importance of drug repositioning to face COVID19. Among its multiple complications, severe pneumonia and thromboembolism-related death are the most aggressive. Thus, we aimed to monitor the mechanism of SARS-CoV-2 to exert the severe illness and death to explore targets for therapies. Our objective was achieved by determination the cutoff of the novel biomarker; Human platelets membrane glycoprotein IIb/IIIa (CD41/CD61) (GPIIb/IIIa) in in microparticle free plasma separated from peripheral blood samples from COVID19 patients and health subjects using ELISA technique. We observed that elevated level of GPIIb/IIIa in COVID19 patients, especially, those with severe illness including severe pneumonia and pulmonary embolism compared to control subjects. Our data indicated the relevance of determination GPIIb/IIIa as a diagnostic and prognostic biomarker for hematopoietic disorders including platelets aggregation and pulmonary embolism in COVID19 patients suffered from severe illness. We concluded that determination of GPIIb/IIIa level by easy, reliable and low-cost ELISA kit help in early diagnosis of hematopoietic disorders in COVID19 patients and may help in improving the clinical outcomes and treatment of COVID19 patients. Addition of GPIIb/IIIa inhibitors (synthetic or natural products) to the treatment protocol of COVID19 patients may add benefit in improving the clinical outcomes in COVID19 patients.