4.1. The inclusion criteria are: 1) Laboratory confirmed COVID-19 (diagnosis of SARS-CoV-2 via reverse transcriptase polymerase chain reaction as per the World Health Organization protocol or by nucleic acid based isothermal amplification), positive test prior to hospital admission OR within first 5 days (ie 120 hours) after hospital admission 2) Admitted to hospital for COVID-19, 3) One D-dimer value above ULN (within 5 days (ie 120 hours) of hospital admission) AND EITHER: a. D-Dimer ≥2 times ULN OR b. D-Dimer above ULN and Oxygen saturation ≤ 93% on room air, 4) > 18 years of age, 5) Informed consent from the patient (or legally authorized substitute decision maker).

4.1. The inclusion criteria are: 1) Laboratory confirmed COVID-19 (diagnosis of SARS-CoV-2 via reverse transcriptase polymerase chain reaction as per the World Health Organization protocol or by nucleic acid based isothermal amplification), positive test prior to hospital admission OR within first 5 days (ie 120 hours) after hospital admission 2) Admitted to hospital for COVID-19, 3) One D-dimer value above ULN (within 5 days (ie 120 hours) of hospital admission) AND EITHER: a. D-Dimer ≥2 times ULN OR b. D-Dimer above ULN and Oxygen saturation ≤ 93% on room air, 4) > 18 years of age, 5) Informed consent from the patient (or legally authorized substitute decision maker).