PROS1 and hepatitis A virus infection: Hypercoagulability panel (prothrombin, activated partial thromboplastin time, fibrinogen, protein C, protein S, antithrombin, homocysteine, DRVVT (dilute Russell's viper venom time), antiphospholipid antibody syndrome (APS) antibodies were normal, though D-dimer was elevated. All workups for potential infections, including hepatitis B, hepatitis C, Mycobacterium tuberculosis, and testing for streptococcal and aspergillus antigens, were negative.