D dimer

The laboratory values were defined to be abnormal when they are out of their normal prescribed range. These ranges for various parameters are as follows: IL-6, 0 to 7 pg/mL; CRP, 0.068 to 8.2 mg/L; white blood cells, 3.97 to 9.15 × 10⁹/L; neutrophils, 2 to 7 × 10⁹/L; leucocytes, 0.8 to 4.0 × 10⁹/L; eosinophils, 0.02 to 0.5 × 10⁹/L; total T cells, 690 to 2540/μL; CD4, 410 to 1590/μL; CD8, 190 to 1140/μL; and D-dimer, less than 0.55 mg/L. The values were defined as low or high if they were below or above the indicated values.^4
,18 (link) The levels of cytokines and D-dimer were measured using chemiluminescence immunoassay assay kits (CRP from Beckman, Carlsbad, Calif; IL-6 from Roche Diagnostics, Mannheim, Germany; and D-dimer from Siemens Healthineers, Marburg, Germany).

Blood from all subjects was collected into 3.2% trisodium citrate tubes (9:1 v/v, Becton Dickinson) and centrifuged 15 min at 2500g at room temperature, followed by 20 000g for 10 min. The obtained platelet‐poor plasma was stored in aliquots at −80°C until thawed at 37°C immediately before use. Fibrinogen levels were measured using the Clauss assay (Thrombin Reagent, Siemens Healthineers), factor VIII (FVIII) levels using a one‐stage clotting assay and FXIII levels with a chromogenic assay using the Berichrom FXIII kit (Siemens Healthineers). In addition, levels of D‐dimer (Siemens Healthineers) and anti‐Xa (Werfen) were routinely measured. All parameters were measured on the Sysmex CS5100 coagulation analyzer (Siemens Healthcare Diagnostics B.V.). Other relevant parameters (e.g., C‐reactive protein) were routinely measured. PAI‐1 levels were measured using the human Serpin E1/PAI‐1 DuoSet ELISA kit (DY1786, R&D Systems) according to the protocol provided by the manufacturers, with some minor changes in the volumes of samples, detection antibody, and streptavidin‐horseradish peroxidase (50 µl instead of 100 μl). Values above the standard of the ELISA were given the maximum value of the standard (40 ng/ml).